View original document

The full text on this page is automatically extracted from the file linked above and may contain errors and inconsistencies.

Business
Review
Federal Reserve Bank o f Philadelphia
Septem berOctober 1993




ISSN 0 0 0 7 -7 0 1 1

Business
Review

The BUSINESS REVIEW is published by the
Department of Research six times a year. It is
edited by Sarah Burke. Artwork is designed
and produced by Dianne Hallowell under the
direction of Ronald B. Williams. The views
expressed here are not necessarily those of this
Reserve Bank or of the Federal Reserve System.

SUBSCRIPTIONS. Single-copy subscriptions
for individuals are available without charge. Insti­
tutional subscribers may order up to 5 copies.
BACK ISSUES. Back issues are available free of
charge, but quantities are limited: educators may
order up to 50 copies by submitting requests on
institutional letterhead; other orders are limited to 1
copy per request. Microform copies are available for
purchase from University Microfilms, 300 N. Zeeb
Road, Ann Arbor, MI 48106.
REPRODUCTION. Permission must be
obtained to reprint portions of articles or whole
articles. Permission to photocopy is unrestricted.
Please send subscription orders, back orders,
changes of address, and requests to reprint to
Publications, Federal Reserve Bank of Philadelphia,
Department o f Research and Statistics, Ten
Independence Mall, Philadelphia, PA 19106-1574,
or telephone (215) 574-6428. Please direct editorial
communications to the same address, or telephone
(215) 574-3805.




SEPTEMBER/OCTOBER 1993

DO AMERICANS SAVE TOO LITTLE?

B. Douglas Bernheim & John Karl Scholz
Should policymakers encourage public
saving through deficit reduction, or pri­
vate saving through tax incentives and
pension policies?
Economists debate
about which method is more efficacious.
Doug Bernheim and John Karl Scholz
examine the private saving side of the
debate by raising two questions: Is there
reason to be concerned about the rate of
private saving? And are there any effec­
tive and reliable methods of promoting
private saving?
HIGHWAYS AND EDUCATION:
THE ROAD TO PRODUCTIVITY?

Gerald A. Carlino
The slowdown in productivity growth in
recent decades has become a cause for
concern. The decline in investment in
public infrastructure and the decline in
educational quality may have played a
role in this slowdown. Can improved
infrastructure, such as more roads, and
higher educational attainment lead to in­
creased productivity? Jerry Carlino looks
at some of the factors involved in regional
productivity to determine if more high­
ways, increased education, and produc­
tivity growth are indeed linked.

Do Americans Save Too Little?

c

B. Douglas Bernheim* & John Karl Scholz*

Ita-Jince the mid-1980s, low rates of national
saving in the United States have generated an
enormous amount of concern among both
economists and policymakers. Proposals to
address these concerns fall into two broad
categories: policies designed to increase public

*B. Douglas Bernheim is the John L. Weinberg Professor
of Economics and Business Policy, Princeton University.
John Karl Scholz is an assistant professor of economics,
University of Wisconsin, Madison. When this article was
written, Bernheim was a visiting scholar in the Research
Department of the Philadelphia Fed. The authors gratefully
acknowledge the work of Robert Avery and Arthur
Kennickell, who developed a clean copy of the 1983-86
Survey o f Consumer Finances and provided extensive docu­
mentation.




saving and policies intended to promote pri­
vate saving. The former is synonymous with
deficit reduction, while the latter includes tax
incentives, pension policy, and strategies for
discouraging the use of private debt. Some
economists argue that deficit reduction is the
most reliable and efficacious method of in­
creasing national saving (Summers, 1985), while
others maintain that restoring adequate rates of
private saving is essential (Bernheim, 1991). To
evaluate the merits of strategies that target
private saving, we must resolve two issues.
First, aside from the obvious fact that private
saving is one component of national saving, is
there reason to be concerned about the rate of
private saving? Second, are there any effective
and reliable methods of promoting private sav­
ing?
3

BUSINESS REVIEW

SEPTEMBER/OCTOBER1993

cal in all respects except that the elderly make
THE ADEQUACY
up a larger fraction of the population in A than
OF HOUSEHOLD SAVING
According to common wisdom, Americans in B. Since households tend to accumulate
consume too much and save too little. This wealth prior to retirement and spend wealth
impression is largely traceable to widely publi­ thereafter, we would expect to observe a higher
cized statistics on aggregate personal saving. rate of aggregate personal saving in country B.
International comparisons reveal that U.S. Indeed, in an economy with no growth in either
households save significantly less than their population or productivity, dissaving by retir­
foreign counterparts. Between 1980 and 1991, ees could completely offset saving by workers:
Americans saved 6.4 percent of disposable per­ in principle, regardless of how well individual
sonal income, compared with 9.8 percent for households prepared for retirement, we might
OECD Europe and 15.7 percent for Japan (Or­ observe virtually no aggregate personal sav­
ganization for Economic Cooperation and De­ ing. Thus, ultimately, we can judge the ad­
velopment, 1992). And since the mid-1980s, the equacy of personal saving only by examining
rate of household saving in the U.S. has been microeconomic data on the behavior of indi­
vidual households.
well below its historical average (Figure 1).
Generally, the available evidence suggests
Although these statistics raise legitimate
concerns, they do not provide definitive evi­ that American workers have prepared poorly
dence of a problem. As measured, personal for retirement. Diamond (1977) found that,
saving excludes capital gains. Thus, in prin­ during the 1960s, 40 percent of couples and
ciple, households can accumulate wealth at a more than 50 percent of unmarried individuals
rapid rate even when their measured rates of reported that after retirement they received no
saving are low. Rates of personal saving can money income from assets. At age 60, nearly 30
also vary across both
time and countries for
FIGURE 1
reasons unrelated to the
adequacy of saving con­
Rate of Personal Saving,
sidered from the per­
National Income Accounts
spective of individual
households.1*To under­
Percent of disposable income
stand this second point,
10
consider the following
hypothetical example.
8
Envision two countries,
A and B, that are identi­

1Indeed, Meyer, 1992, ar­
gues that demographic differ­
ences account for roughly onethird of the gap in personal
saving relative to GNP be­
tween Germany and the U.S.
during the 1980s and roughly
two-thirds of the gap between
Japan and the U.S.

4 FRASER
Digitized for


70

72

74

76

78

80

82

84

86

88

90

Year

FEDERAL RESERVE BANK OF PHILADELPHIA

Do Americans Save Too Little?

B. Douglas Bemheim & John Karl Scholz

percent of middle-class individuals lacked suf­ particular assets were accumulated for retire­
ficient wealth to replace two years' worth of ment or for some other purpose. Consequently,
income. Similarly, Hamermesh (1984) con­ the comparison between estimated trajectories
cluded that, during the 1970s, most elderly and simulated trajectories may provide an
individuals had not accumulated sufficient re­ overoptimistic picture of the adequacy of house­
sources to sustain their accustomed standards hold saving.
of living. Indeed, consumption shortly after
We show graphic depictions (Figures 2 and
retirement exceeded the highest sustainable 3) of a simulation for a household with the
level of consumption by an average of 14 per­ following characteristics: age 27 (as of 1991),
cent. Hamermesh also found that within a few two years of college education, married, two
years of retirement most retirees were forced to workers with total current earnings of $60,540,
reduce their expenditures substantially.2
and the primary earner covered by a private
Asset Accumulation Profiles. More recent pension plan. This household's optimal trajec­
evidence on the adequacy of saving appears in tory of consumption and after-tax earned in­
Bernheim and Scholz (1992a). Using an elabo­ come (including pensions and Social Security)
rate model of household decision-making, we is shown in constant 1991 dollars (Figure 2,
simulated asset accumulation profiles (trajec­ page 7).4 Note that after-tax earnings rise steeply
tories) that households should follow (given early in life. Earnings growth continues at a
the assumptions of the model) to prepare ad­ reduced level until the individual reaches age
equately for retirement.3 We then compared 55, at which point it begins to fall. After retire­
these simulated profiles with ones estimated ment, earned income consists of Social Security
from recent surveys of households' actual sav­ and private pension benefits. Since pensions
ing behavior. (For a more detailed description are not perfectly indexed for inflation, real
of the model, see Explanation o f the Model.)
benefits decline gradually over time.
The simulation model describes only the
As a direct consequence of the household's
accumulation of assets for retirement. There rapid earnings growth early in life, it saves
are, of course, many reasons to save. House­ nothing for retirement prior to age 30. Between
holds should take precautions against the pos­ ages 30 and 80, the consumption trajectory is
sibility of illness, layoff, disability, death, and relatively flat. This flat trajectory reflects the
other risks for which they are imperfectly in­ household's preference for a stable standard of
sured. In addition, most households accumu­ living. However, during the 30s and 40s, con­
late resources to pay for large expenses such as sumption is elevated relative to the 60s and 70s.
college tuition or the purchase of an automo­ This pattern results from changes in household
bile. For some individuals, saving is motivated composition: between the ages of 30 and 50, the
in part by the desire to leave a substantial typical household incurs significant child-rear­
bequest upon death. Unfortunately, when ex­ ing costs. Consumption declines rapidly after
amining the data, we cannot determine whether age 80 until, at age 101, it matches after-tax
retirement benefits. Falling survival probabili­
ties cause this end-of-life decline. Since there is
a relatively low probability of reaching age 90,
2Other economists have reached somewhat more opti­
mistic conclusions. See Kotlikoff, Spivak, and Summers,
1982.
developm ent of this model was sponsored by Merrill
Lynch & Co., Inc., and is described in Bernheim, 1992b.




4We use the word "trajectory" to describe the manner in
which an economic variable, such as consumption, income,
or wealth, evolves as the household ages.

5

Explanation of the Model

BUSINESS REVIEW

SEPTEMBER/OCTOBER1993

Our simulation model reflects a "life-cycle" approach to the average household's financial
decision-making process. It takes into account the fact that predictable changes in household
earnings resulting from age and stage of career may not match up very well with consump­
tion needs. For example, the financial needs of most households are usually highest during
the child-rearing years, while household earnings usually reach their highest point after
children have left home. The household varies its rate of saving in order to achieve a better
match between the ability to spend and the need to spend. It saves least in years when
spending needs are high and more in years when spending needs decline.3 The model
forecasts households' future income and derives the optimal consumption (and thus saving)
trajectories consistent with those income forecasts.
Our life-cycle calculations account for a variety of current and future household charac­
teristics, including age, income level, pension coverage, education, marital status, gender (if
unmarried), and household composition (the numbers of children and dependent adults).b
The model also projects and adjusts for future macroeconomic conditions that ought to affect
savings behavior, including interest rates, inflation rates, and baseline wage growth. In
addition, the model provides a realistic treatment of income taxes, payroll taxes, and social
security benefits.
To conduct simulations, one must also choose values for several "preference parameters."
For example, the model includes a parameter commonly known as the "pure rate of time
preference," which expresses the value that a household places on future consumption
relative to current consumption.0The value of this particular parameter has a profound effect
on the simulation results. When the pure rate of time preference is sufficiently low, it is
optimal for the household to save nothing. For this reason, the absence of saving is not
necessarily the result of irrationality. Rather, it may simply reflect impatience.
We have calibrated our model (that is, chosen values for the preference parameters) so that
the simulations produce a standard of living during retirement that is roughly comparable
to the standard of living enjoyed prior to retirement.11 Consequently, it is appropriate to
interpret our results as follows: if households fall significantly short of simulated asset
accumulation targets, they will ordinarily be forced to accept serious reductions in their
standards of living after retirement.
aWhen spending needs are sufficiently high relative to income, a household may wish to liquidate or
borrow against accumulated assets. Once assets are exhausted, it may be optimal for the household to
borrow against future income. However, for most households, it is extremely difficult to obtain sizable
unsecured loans. Our model therefore imposes a "liquidity constraint," which ensures that the household's
net wealth remains positive.
bOur calculations reflect the fact that larger households benefit from significant economies of scale.
Research on household scale economies indicates that two adults in a household can obtain the same
standard of living as one adult living alone with added expenditures of slightly more than 40 percent.
Research also shows that the financial impact of adding one adult to a household is roughly equivalent to
adding 2.5 children. See Cutler and Katz, 1992.
cOther important preference parameters include a minimum subsistence level for consumption and a
parameter known as the "intertemporal elasticity of substitution," which measures the extent to which the
household's willingness to trade off current consumption for future consumption is affected by the level
of current consumption relative to future consumption.
dSpecifically, we use a pure rate of time preference equal to the product of 0.99 and one-year genderspecific survival probabilities (taken from standard life tables). The minimum consumption level is set
equal to $10,000 (measured in 1991 dollars), and is adjusted for family size. A value of 0.25 is used for the
intertemporal elasticity of substitution.

Digitized for
6 FRASER


FEDERAL RESERVE BANK OF PHILADELPHIA

Do Americans Save Too Little?

B. Douglas Bernheim &John Karl Scholz

the household would prefer to accept a lower of the best available sources of data on house­
standard of living at age 90 and later (if it hold balance sheets.6
survived that long) in favor of a higher stan­
dard of living earlier in life.
The associated optimal trajectory of retire­
6See Avery and Elliehausen, 1988, and Avery and
ment assets is also depicted (Figure 3). Assets Kennickell, 1988, for a more complete discussion of the SCF.
accumulate at an increasing
rate from age 30 to retire­
FIGURE 2
ment, peak at retirement,
then decline steadily until
Simulated After-Tax Income and
they are exhausted at age
Consumption Trajectories
100 .
We then estimated actual
Dollars (thousands)
asset trajectories using data
70
from the Survey o f Consumer
Finances (SCF) for 1983 and
1986.5 The Board of Gover­
nors of the Federal Reserve
(in conjunction with other
federal agencies) sponsored
the SCF, recognized as one
After-tax income
1Spending
5Our measure of accumulated
net worth includes stocks and mu­
tual funds, bonds, checking and sav­
ings accounts, IRA and Keogh ac­
counts, money market accounts, cer­
tificates of deposit, profit-sharing
and thrift accounts, the dollar cash
value of whole life insurance, and
other financial assets, as well as eq­
uity in property (other than primary
residences) and business assets, less
credit card, consumer, and other
debt. This measure excludes all as­
sets and liabilities associated with
homes and vehicles, since house­
holds appear to have a strong aver­
sion to paying living expenses dur­
ing retirement by drawing down the
equity in their homes (see Venti and
Wise, 1989). Also, it seems likely
that few individuals save for retire­
ment by accumulating wealth in the
form of vehicles. Accumulated
wealth for 1983 is expressed in 1986
dollars using the Consumer Price
Index.




27 33 39 45 51 57 63 69 75 81 87 93 99
30 36 42 48 54 60 66 72 78 84 90 96 102
Age
FIGURE 3

Simulated Wealth Trajectory
Retirement assets (thousands)
400

27 33 39 45 51 57 63 69 75 81 87 93 99
30 36 42 48 54 60 66 72 78 84 90 96 102
Age
7

BUSINESS REVIEW

SEPTEMBER/OCTOBER 1993

Our analysis allows us to compare actual earner completed college are depicted in Figure
and simulated optimal behavior. The results 5. The contrast between Figures 4 and 5 is
for households in which the primary worker remarkable. In cases where the household
has not completed college are shown in Figure head completed college, both simulated and
4. In this figure, "actual" refers to the estimated estimated changes in wealth rise steeply with
change in wealth (measured as a fraction of age. Moreover, simulated asset accumulation
wage income) for the representative household tracks actual asset accumulation remarkably
within each age group (calculated using the well. Taken at face value, Figure 5 suggests that
SCF); "Sim/no pen" indicates the simulated highly educated households saved adequately
change in wealth (again as a fraction of wage for retirement between 1983 and 1986.
Although it is tempting to conclude that
income) for a representative household with­
out pension coverage for the primary earner; inadequate saving is largely confined to those
and "Sim/pen" denotes the simulated change without a college education, this conclusion
in wealth for a representative household with must be tempered by two considerations. First,
pension coverage for the primary earner. Note as is apparent from Figure 1, personal saving
that the simulated change in wealth rises steeply declined sharply after the 1983-86 period on
with age. This steep increase in assets results which the estimates are based. Using a sample
from two factors. First, during most of an of relatively young individuals (ages 25 through
individual's working life wages rise more rap­ 44) surveyed in early 1992, Bernheim (1992a)
idly than consumption (see Figure 2). Second, found much more pervasive evidence of inad­
reinvested capital income rises as the house­ equate saving. Second, the model probably
hold accumulates assets. In contrast, the esti­ understates the amount of wealth that each
mated change in wealth does not vary signifi­ household ought to accumulate. The most
cantly with age. By the time the household obvious reason for this discrepancy is that the
reaches middle age, simu­
lated asset accumulation
FIGURE 4
exceeds actual accumula­
Rates of Asset Accumulation
tion by a wide margin.7
Overall,between 1983 and
No College Degree
1986, households without
Annual change in wealth as a multiple of earnings
a college education saved
0.25
far less than the simula­
tion model predicts (Fig­
ure 4).
Results for households
in w hich the prim ary

7Although estimated asset ac­
cumulation is actually higher at
ages 27 and 32, this is of little
consequence; recall that the data
reflect saving for a variety of pur­
poses aside from retirement.

Digitized for8 FRASER


FEDERAL RESERVE BANK OF PHILADELPHIA

Do Americans Save Too Little?

B. Douglas Bernheim & John Karl Scholz

simulations envision retirement planning as
the sole motive for saving.8
To the extent that many households prepare
poorly for retirement, there is cause to be con­
cerned about the rate of personal saving, per se.
Historically, pension policy and tax policy have
been the two most important tools for stimulat­
ing personal saving. We will discuss evidence
on the efficacy of each of these strategies in turn.

possibility that policies affecting private pen­
sions may have powerful effects on aggregate
personal saving. Whether these effects would
actually materialize depends on the way work­
ers would respond to an expansion of private
pension coverage. Economic theory suggests
that such an expansion would simply crowd
out other forms of personal saving: once work­
ers realize that their employers are, in effect,
saving for them, workers will save less them­
PENSION POLICY
selves. The simulation results presented in the
In recent years, the accumulation of assets in previous section illustrate this principle. How­
private pension plans has accounted for a sub­ ever, previous studies of personal saving have
stantial fraction of personal saving (Bernheim generally failed to find evidence to support the
and Shoven, 1988). This observation raises the notion that private pensions significantly re­
duce other forms of personal saving.9 Depend­
ing on whether we credit the theoretical analy­
8In addition, it is quite likely that the model overstates
sis or the empirical studies, we can reach dra­
mortality probabilities (since it does not make any allow­
matically different conclusions about the effect
ance for the fact that these probabilities are projected to
of pension policy on aggregate personal saving.
decline in the future), understates the importance of health
The analysis described in the preceding sec­
and long-term care costs for the elderly, and fails to consider
tion raises an intriguing possibility: if the be­
the effects of mounting economic pressures that may force
Congress and employers to scale back existing retirement
havior of those with a college education (and
benefits.
higher average incomes) conforms to the pre­
dictions of standard eco­
nomic theories, while the
FIGURE 5
behavior of those without
Rates of Asset Accumulation
a college education (who
have lower average in­
College Degree
comes) does not, perhaps
private pensions do dis­
Annual change in wealth as a multiple of earnings
p lace p erso n al saving
0.5
among the college edu­
cated, but not among the
rest of the population. In
that case, pension policy
could be an effective tool
for stimulating total per­
sonal saving, so long as it
is primarily used to pro-

27

32




37

42

47
Age

52

57

62

9See, for example, the review
in Shefrin and Thaler, 1988, par­
ticularly pages 622-24.

9

BUSINESS REVIEW

SEPTEMBER/OCTOBER1993

vide incentives for expanded coverage among saving displacement effect simply because they
lower income, generally less educated, work­ did not distinguish between households on the
ers.
basis of education (or permanent income).
To investigate this idea, we estimated equa­
The contrast between Figures 6 and 7 points
tions that explained the median value of house­ to a clear and important conclusion for pension
hold wealth as a function of age, total house­ policy: private pensions displace personal
hold earnings, private pension coverage, and wealth accumulation only when the head of the
educational attainment. We then used these household is college-educated. This observa­
equations to project asset accumulation pro­ tion aligns with the evidence on the adequacy
files.
of personal saving described in the first section
Results for the median household in which of this article. Indeed, our evidence broadly
the primary earner has not completed college supports a more general conclusion: collegeare presented in Figure 6. Note that pension educated households behave in the manner
eligibility has little or no effect on the actual predicted by standard economic theories of
path of household wealth accumulation. From saving, while less well-educated households
a statistical perspective, the estimated equation do not. Past and current policies have been
supports the notion that, at every age, less more successful at stimulating the expansion of
educated households with private pensions pension coverage among college-educated
accumulate wealth at the same rate as those
without private pensions.
Results for households in which the primary
10It is unlikely that the observed relationship between
earner has completed college are displayed in
pension coverage and saving results from spurious factors,
Figure 7. Statistically, the data decisively reject since such factors would presumably also have produced
the premise that the rate of asset accumulation the same patterns for less educated households.
is unrelated to pension eli­
gibility. Note that those
FIGURE 6
eligible for pensions accu­
Estimated Wealth Trajectories
mulate resources at a sig­
nificantly slower rate than
No College Degree
those without pensions.
Assets/ earnings
Remarkably, at age 62, the
1.8
gap between the assets of
these two groups is almost
identical in magnitude to
the predicted gap that
emerges from our compu­
tations. These patterns are
strongly consistent with
the view that private pen­
sions displace other per­
sonal saving for collegeeducated hou seholds.10
These results suggest that
other studies may have
failed to find a significant
Digitized for
10 FRASER


FEDERAL RESERVE BANK OF PHILADELPHIA

Do Americans Save Too Little?

B. Douglas Bernheim & John Karl Scholz

greater future consumption, even if the house­
hold were to save a bit less out of its current
income.) Indeed, empirical estimates of the
sensitivity of saving to the after-tax rate of
return (called the interest elasticity of saving)
vary widely (Boskin, 1978; Summers, 1981; and
Hall, 1988).
Individual Retirement Accounts.
Most
current proposals to provide tax incentives for
saving are patterned after individual retire­
ment accounts (IRAs). IRAs were established
as part of the 1974 Employee Retirement In­
come Security Act to give workers not covered
by employer-provided pension plans added
TAX POLICY
The most commonly discussed strategies for incentives to accumulate resources for retire­
stimulating personal saving entail reductions ment. In 1981, IRA eligibility was extended to
in the taxation of capital income. Economic all taxpayers. Subsequently, the Tax Reform
theory suggests that households will respond Act of 1986 curtailed the tax-deductibility of
to a higher after-tax rate of return on savings by IRA contributions for high income households.
increasing future consumption relative to cur­ The existence of an income cap for IRAs raises
rent consumption. However, theory does not an important question: does the sensitivity of
saving to the after-tax rate of return vary sys­
n ecessarily p red ict that cu rren t saving w ill rise.
(The reason is that a higher rate of return will tematically across income classes? The answer
make wealth grow more rapidly, enabling to this question makes it possible to determine
whether the current sys­
tem targets the most re­
FIGURE 7
sponsive groups.
Estimated Wealth Trajectories
Simulations based on
the
model
described in this
College Degree
article suggest that higher
Assets/ earnings
income individuals will be
5.0
m uch more responsive
than lower income indi­
Pension
4.0
No pension
viduals to changes in the
after-tax rate of return.
Averaging across indi­
3.0
viduals with pensions and
individuals without pen­
2.0
sions, the simulations im­
ply that saving by 35-year1.0
old, co llege-ed u cated
h ou seh old s w ould in ­
0.0
crease by 10.2 percent in
response to a permanent
one-percentage-point in-

workers than among those with less education.
Analysis of the SCF data reveals that 75.2 per­
cent of college-educated husbands are covered
by private pensions. In contrast, only 55.7
percent of husbands who lack a college educa­
tion are covered by private pensions. In other
words, the current system is quite effective at
providing pensions to those individuals who
reduce other saving in response and much less
effective at providing coverage to those indi­
viduals for whom pensions would represent
incremental saving.




li

BUSINESS REVIEW

crease in the before-tax rate of return, while the
saving of 35-year-old, high-school-educated
households would fall by 4.5 percent. Conse­
quently, policies that provide tax incentives for
saving exclusively to lower income households
exclude those individuals most likely to in­
crease saving in response to tax incentives;
indeed, such policies could actually reduce
aggregate personal saving.
This positive relationship between income
and the interest elasticity of saving results from
a natural economic consideration, rather than
from some peculiar feature of the simulation
model. It is natural to assume that when plan­
ning for the future, most households are con­
cerned first and foremost with saving enough
to assure themselves of some minimum stan­
dard of living. As lifetime resources increase,
households have more discretion to allocate
resources in a manner that increases consump­
tion above and beyond this minimum standard
both today and in the future.
For low income households, saving to achieve
some minimum future consumption is prob­
ably far more important than saving to fund
incremental consumption. Saving to provide
for minimum consumption is, in effect, saving
for a fixed target. An individual who saves to
achieve some target will reduce saving in re­
sponse to an increase in the rate of return
(Bernheim and Shoven, 1988). Thus, because
target saving dominates the simulated behav­
ior of these households, they exhibit a low or
negative interest elasticity of saving. For high
income households, however, saving to fund
incremental consumption is probably far more
important than saving to achieve the minimum
consumption target. Incremental saving domi­
nates the simulated behavior of these house­
holds. Thus we observe a high interest elastic­
ity of saving among higher income, well-edu­
cated households. Discretionary saving to fi­
nance consumption over and above the target
responds positively to an increase in the rate of
return.
Digitized 12
for FRASER


SEPTEMBER/OCTOBER 1993

Of course, in the preceding sections, we
observed that the behavior of less educated
(generally lower income) households may not
conform to standard economic theories. Al­
though this finding reduces our faith in the
applicability of our simulation results, it does
not reverse our conclusions concerning the
interest elasticity of saving. The notion that
households will respond to a change in the
after-tax rate of return is predicated on the
assumption that households rationally antici­
pate and plan for future economic contingen­
cies. To the extent that this assumption proves
incorrect, there is no particular reason to be­
lieve that lower income households will re­
spond to a change in the after-tax rate of return
in the first place.
Tax Policy Initiatives. Two prominent cur­
rent policy initiatives would reverse the direc­
tion of the 1986 reforms and improve tax incen­
tives for saving to households in higher income
brackets. Family saving accounts (FSAs), pro­
posed by the Bush administration, would allow
single individuals with adjusted gross incomes
(AGI) below $60,000 and married couples with
AGI below $120,000 to make contributions of
up to $2500 to qualified accounts. The FSA
proposal is an example of a "back-loaded"
system: contributions are nondeductible, but
accumulated funds are not taxed upon with­
drawal. An alternative proposal, the BentsenRoth "super-IRA/' would allow individuals to
contribute up to $2000 to either a traditional or
a back-loaded IRA.11

n On August 3, 1992, the Senate Finance Committee
approved H.R. 11, the Revenue Bill of 1992. Like the BentsenRoth super-IRA, this bill would restore the deductibility of
IRA contributions for all taxpayers and establish new backloaded IRAs. Contributions to back-loaded IRAs could be
withdrawn without penalty after five years. The bill would
also allow taxpayers to make penalty-free early withdraw­
als from IRAs for the purchase of a first house, for higher
education expenses, for medical expenses, and for long
spells of unemployment.

FEDERAL RESERVE BANK OF PHILADELPHIA

Do Americans Save Too Little?

B. Douglas Bernheim & John Karl Scholz

Unfortunately, there are sound conceptual by borrowing do not increase household sav­
reasons to doubt the effectiveness of extending ing. Instead, by reducing federal tax receipts,
eligibility for IRA-style accounts to higher in­ they add to the federal budget deficit and
come households. First, contributions are depress national saving. Once again, it is more
capped. Under the current system, a single likely that high income households (who pos­
taxpayer, for example, can make no more than sess greater wealth, financial sophistication,
$2000 in tax-deductible contributions. For an and access to credit markets) would engage in
individual taxpayer who would have saved borrowing or asset shifting and thus defeat the
more than $2000 in the absence of IRAs, the purpose of the program.
availability of an IRA does not affect the costs
Empirical evidence on the efficacy of IRAs is
or benefits that might result from an additional mixed. Gale and Scholz (1992) find little evi­
dollar of saving and, therefore, provides no dence that IRAs stimulated household saving
incentive on the margin for the taxpayer to between 1983 and 1986. Venti and Wise (1986,
increase saving. In such cases, the IRA consti­ 1987, 1990, 1991) and Feenberg and Skinner
tutes a "giveaway" of public funds (it reduces (1989) suggest that most IRA contributions
federal tax receipts but does not promote more during this period represent net increases in
saving). In addition, the IRA may actually household saving. Joines and Manegold (1991)
induce the taxpayer to increase consumption, conclude that the effects of IRAs on household
since it increases his or her total after-tax re­ saving are unlikely to be as large as the esti­
sources. For both of these reasons, the IRA mates of Venti and Wise and may be as small as
would contribute to a lower rate of national the estimates of Gale and Scholz.
saving. These concerns are of little significance
An alternative proposal to promote house­
for low income households, since few of them hold saving, based on "premium saving ac­
would save more than $2000 in the absence of counts" (PSAs), is described in Bernheim and
the program. It is far more likely that high Scholz (1992b). A PSA system would require
income households would save more than the each taxpayer to save—in total— some fixed
contribution limit. Thus, IRA-style proposals amount (the floor) before becoming eligible to
may be a particularly ineffective vehicle for make contributions to a tax-favored account.
providing tax incentives for saving to high The taxpayer would be eligible to contribute
income households.
each additional dollar of saving to the taxA second reason for doubting the effective­ favored account, up to some limit (the ceiling).
ness of IRA-style accounts for high-income These floors and ceilings would rise with AGI
households is that even if such a taxpayer and certain types of capital income. As with
would not (in the absence of IRAs) have saved IRAs, capital income accrued on balances held
more than the IRA contribution limit in a given in PSAs would be exempt from taxation.12*
year, he or she could take full advantage of the
The use of both floors and ceilings would
IRA deduction either by financing contribu­
tions with previously accumulated assets or by
borrowing. Indeed, the 1991 Tax Guide for
12With this essential structure, a PSA system could be
College Teachers devotes a full page to the issue either front-loaded or back-loaded. Penalties could be
"What If You're Short of Cash to Fund Your established to lock funds into tax-favored accounts for
IRA?" (pp. 229-30). The Guide describes an IRS relatively short periods (e.g., seven years) or until some age
close to retirement (perhaps age 591 /2). Accounts could be
private letter ruling that allows households to
established for specific purposes (e.g., retirement, purchase
finance their IRAs by borrowing. Contribu­ of a house, college education), or the accounts could be
tions funded either by shifting existing assets or unrestricted.



13

BUSINESS REVIEW

create "windows" of program eligibility. Con­
sider, for example, a married couple with an
AGI of $80,000. They might face a floor of $8000
and a ceiling of $12,000. Should they save less
than $8000 in the corresponding tax year, they
would not be eligible to make any contributions
to a tax-favored account. If, on the other hand,
they saved $9500, they would be eligible for
favorable tax treatment on $1500. If they saved
more than $12,000, they would be eligible to
make the maximum contribution of $4000 (the
difference between $8000 and $12,000).
The most important distinctive feature of a
PSA system is that floors and ceilings would
vary with AGI. Eligibility windows could be
positioned to maximize, within each income
class, the number of households receiving tax
breaks on the marginal dollar of saving. Doing
so would maximize the incentive to save more.
Higher-income taxpayers would not be de­
prived of tax incentives for saving; rather, they
would simply be required to save much larger
fractions of their incomes before becoming eli­
gible for PSAs. It would also be much more
difficult for households to take advantage of
tax-favored PSA accounts by shifting assets or
by borrowing because eligibility would be based
on total saving. An individual cannot increase
his total saving by shifting assets from one
account to another or by borrowing to invest.13
To implement a PSA system, one needs to
measure a household's total saving. Bernheim
and Scholz (1992b) propose the following mea­
sure:14156
Net purchases of assets (i.e., total purchases

13The administrative feasibility of monitoring total sav­
ing for each taxpayer is discussed in Bernheim and Scholz,
1992b.
14Many economists would define saving as the change in
the stock of wealth between two points in time. If one
adopts this definition, saving is very hard to measure: one
would need to assess the market value of all assets every




SEPTEMBER/OCTOBER1993

minus total sales) for assets on which investors
receive capital gains and losses
plus
The January 1 to January 1 change in cash
account balances (e.g., bank accounts),
minus
The January 1 to January 1 change in total
debt (mortgages, consumer credit, etc.).
In effect, saving is defined as the incremental
resources that an individual sets aside in any
year over and above reinvested capital gains.15,16
Now we'll evaluate the effects of three dis­
tinct strategies for promoting household sav­
ing: an IRA-like program with an AGI cap
(hereafter referred to as the "standard IRA"
system), an IRA-like program without an AGI
cap (hereafter referred to as the "universal
IRA" system), and a PSA system. We compare
the cost-effectiveness of extending tax incen­
tives for saving to higher-income taxpayers
through universal IRAs and PSAs.
Sample schedules that define eligibility win­
dows for each level of AGI for a PSA system are
given in Table 1. Separate schedules are given
for married couples and single individuals.
The schedules are chosen to maximize the ben­

year. The definition used in the text represents a compro­
mise between economic logic and administrative feasibil­
ity.
15Note that it is possible to compute this measure of
saving without assessing the value of unrealized capital
assets, since, by definition, unrealized gains are fully rein­
vested.
16If this definition of saving is employed, it is also impor­
tant to adjust each taxpayer's eligibility floors and ceilings
upward by the amount of capital income other than capital
gains. See Bernheim and Scholz, 1992b, for a detailed
discussion of this issue.

FEDERAL RESERVE BANK OF PHILADELPHIA

Do Americans Save Too Little?

B. Douglas Bernheim & John Karl Scholz

eficial effects of the program within each popu­
lation subgroup.17 To facilitate comparisons
with IRAs, we have adopted window widths of
$2000 per year for single households, $2250 per
year for married couples with one earner, and
$4000 per year for married couples with two
earners. For example, a dual-earner married

17Note that the floor rises with income at different rates
for married couples (16.7 cents for each dollar of income
over $34,000) and single individuals (34 cents for each
dollar of income over $42,000). Since actual patterns of
saving differ by marital status, different schedules must be
used to maximize the beneficial effects of the program.

couple with an AGI of $30,000 and no capital
income would have a floor of $0 and a ceiling of
$4000 (Table 1). In contrast, a couple with an
AGI of $120,000 and dividend and interest
income of $2000 would have a floor of $16,362
(.167 x $86,000 + $2000) and a ceiling of $20,362.
The standard and universal IRA systems
differ from the PSA proposal in that they
anchor the eligibility window at $0 for all in­
come classes and make no adjustment for capi­
tal income. The standard IRA system phases
out deductible contributions for married couples
with incomes between $40,000 and $50,000 and
for single taxpayers with incomes between

TABLE l a

Deductible Contribution Formula
Married Couples

If your income is

Deductible Qualified
Contribution Floor
(Added to Capital Income)

Deductible Qualified
Contribution Ceiling
(Added to Floor)

Less than $34,000

0

$2250 or $4000

.167x (Income-34,000)

$2250 or $4000

Greater than $34,000

Single Households

If your income is

Deductible Qualified
Contribution Floor
(Added to Capital Income)

Deductible Qualified
Contribution Ceiling
(Added to Floor)

Less than $42,000

0

$2000

.34 x (Income-42,000)

$2000

Greater than $42,000

aFor the purpose of comparison with IRAs, married couples with one earner are allowed to contribute $2250 and
married couples with two earners can contribute $4000. In the actual implementation of this proposal we see no
compelling reason to make this distinction.




15

BUSINESS REVIEW

$25,000 and $35,000.18 The universal IRA sys­
tem allows all households to make deductible
contributions.19
We compare these plans on the basis of three
criteria. The first criterion is a measure of
effectiveness. Specifically, for each plan, we
estimate the number of households that would
receive a higher after-tax rate of return on the
incremental dollar of saving. We refer to these
households as the IMPACT GROUP. Our sec­
ond criterion is a measure of wasteful subsidi­
zation. Specifically, for each plan, we estimate
the number of households that would make the
maximum eligible contribution to a tax-favored
account w hile continuing to receive the
unsubsidized after-tax rate of return on the
incremental dollar of investment. We refer to
these households as the NO-IMPACT GROUP.
Our third criterion is also a measure of wasteful
subsidization: we calculate the budgetary cost
of subsidizing the NO-IMPACT GROUP. We
refer to this cost as the GIVEAWAY.
Our calculations are once again based on
data obtained from the SCF for 1983 and 1986.
The interested reader is referred to Bernheim
and Scholz (1992b) for details.
Compare the effects of the policies on mar­
ried couples as shown in Table 2. The top panel
shows the size of the IMPACT GROUP. Over­
all, the PSA system provides real incentives to
2.4 million couples, roughly 90 percent more
than the IRA with AGI restrictions and 30
percent more than the universal IRA. The

18It should be noted that the current IRA system differs
from the standard IRA system considered in the text in that
it phases out deductible contributions only for households
that are covered by private pension plans. The current
system is, therefore, a blend of a standard system and a
universal IRA system.
19The IRA-like proposals we simulate are superior to
actual IRA schemes because, in practice, IRA schemes are
susceptible to tax arbitrage strategies involving borrowing
and asset shifting, which our simulations do not capture.

Digitized for
16 FRASER


SEPTEMBER/OCTOBER1993

difference is particularly pronounced in the top
income quintile. By definition, the IRA with
AGI caps ignores these households. Relative to
the universal IRA, the PSA increases the num­
ber of couples receiving marginal incentives in
the top income quintile by nearly 125 percent.
Since, in this sample, over 60 percent of positive
household saving is attributable to households
in the top quintile of the income distribution,
this improvement is particularly important.
The bottom two panels of Table 2 measure
the NO-IMPACT GROUP and the cost of these
ineffective subsidies. The calculations show,
for example, that the PSA system would reduce
the number of households in the NO-IMPACT
GROUP by 1.75 million (28.2 percent) and would
reduce federal expenditures on ineffective sub­
sidies by $2.0 billion (34.0 percent), relative to
the universal IRA. In terms of cost-effective­
ness, the PSA system increases the ratio of the
IMPACT GROUP to the GIVEAWAY by 96.5
percent overall, and by 287.2 percent (that is, by
a factor of almost four) in the top income
quintile. The IRA with AGI caps also effec­
tively reduces ineffective subsidies and bud­
getary cost, but it achieves this reduction by
excluding the very households most likely to
respond to tax incentives.
Note the results for single individuals (Table
3). Under a PSA system, the size of the IMPACT
GROUP would increase significantly relative
to other proposals. The size of the IMPACT
GROUP in the highest income quintile would
more than triple. Moreover, both the size of the
NO-IMPACT GROUP and the GIVEAWAY
would fall relative to the universal IRA. The
result is a 49.7 percent increase in overall costeffectiveness (the ratio of the IMPACT GROUP
to GIVEAWAY), and a 551.3 percent increase in
cost-effectiveness for the top income quintile,
relative to the universal IRA proposal.
Other Initiatives. Pension policies and tax
policies do not exhaust the full range of strate­
gies for stimulating personal saving. One par­
ticular class of policies not discussed here merFEDERAL RESERVE BANK OF PHILADELPHIA

B. Douglas Bernheim & John Karl Scholz

Do Americans Save Too Little?

TABLE 2a

A Comparison of Three Saving-Incentive Proposals,
Married Couples
IRA w/AGI Cap

Universal IRA

PSA

IMPACT GROUP
(in 1000s)
Highest Income Quintile
Full Population

0
1256

102
1840

228
2388

NO-IMPACT GROUP
(in 1000s)
Highest Income Quintile
Full Population

0
3578

1416
6218

817
4467

ANNUAL GIVEAWAY
(in $ millions)
Highest Income Quintile
Full Population

0
2006

1950
5861

1119
3870

COST-EFFECTIVENESS
(ratio of IMPACT group to GIVEAWAY)
Highest Income Quintile
Full Population

—
.3510

.0523
.3139

.2038
.6171

Simulated Effect

Simulations use data from the 1983-86 Survey of Consumer Finances. Saving and column headings are defined
in the text. The PSA schedule is given in Table 1.

its further attention. An accumulating body of
evidence, including that contained in this ar­
ticle, suggests that the behavior of many house­
holds (particularly those with lower incomes)
is not well described by traditional economic
theories. To some, saving decisions appear to
be governed by such factors as habit, mental
accounting, and self-control. Consequently, it
may be possible to design more effective poli­
cies by educating the population or by exploit­
ing the psychology of saving. The Japanese
appear to have had considerable success with



such a strategy during the postwar period
(Horioka, 1988, and Bernheim, 1991). The de­
velopment of a framework for analyzing poli­
cies of this sort is an important research prior­
ity. Bernheim (1993) provides a preliminary
analysis of these issues.
CONCLUSION
The evidence presented in this article sup­
ports the view that many Americans, particu­
larly those without a college education, save
too little. Our analysis indicates that it should
17

SEPTEMBER/OCTOBER 1993

BUSINESS REVIEW

TA B L E 3a

A Comparison of Three Saving-Incentive Proposals r
Single Taxpayers
IRA w/AGI Cap

Universal IRA

PSA

IMPACT GROUP
(in 1000s)
Highest Income Quintile
Full Population

0
454

40
603

134
694

NO-IMPACT GROUP
(in 1000s)
Highest Income Quintile
Full Population

0
1078

350
1405

197
1155

ANNUAL GIVEAWAY
(in $ millions)
Highest Income Quintile
Full Population

0
460

292
845

151
650

COST-EFFECTIVENESS
Highest Income Quintile
Full Population

.9870

.1370
.7136

.8874
1.0677

Simulated Effect

Simulations use data from the 1983-86 Survey of Consumer Finances. Saving and column headings are defined
in the text. The PSA schedule is given in Table 1.

be possible to increase total personal saving
among lower income households by encourag­
ing the formation and expansion of private
pension coverage for such families. It is doubt­
ful that favorable tax treatment of capital in­
come would stimulate significant additional
saving by this group. Conversely, the expan­
sion of private pensions would probably have
little effect on saving by higher income house­
holds. However, these households are more
likely to increase saving significantly in re­
sponse to favorable tax treatment of capital
income. These findings imply that the design of
Digitized for
18 FRASER


the current system, which links eligibility for
IRAs to an AGI cap, and which provides higher
income households with more complete pen­
sion coverage, ensures a minimal impact on
personal saving.
Extending tax incentives for saving to higher
income households is problematic. We have
discussed two competing options: the univer­
sal IRA and the premium saving account (PSA).
Our analysis reveals that the PSA system is a
more cost-effective vehicle for providing in­
centives to those households most likely to
respond to tax incentives.
FEDERAL RESERVE BANK OF PHILADELPHIA

REFERENCES

Do Americans Save Too Little?

B. Douglas Bernheim & John Karl Scholz

Avery, Robert B., and Gregory E. Elliehausen. "1983 Survey of Consumer Finances:
Technical Manual and Codebook," mimeo, Board of Governors of the Federal Reserve
System, August 1988.
Avery, Robert B., and Arthur B. Kennickell. "1986 Survey of Consumer Finances: Technical
Manual and Codebook," mimeo, Board of Governors of the Federal Reserve System,
November 1988.
Bernheim, B. Douglas. The Vanishing Nest Egg: Reflections on Saving in America. Twentieth
Century Fund, 1991.
Bernheim, B. Douglas. "Is the Baby Boom Generation Preparing Adequately for Retirement?
Summary Report," mimeo, Princeton University, August 1992a.
Bernheim, B. Douglas. "Is the Baby Boom Generation Preparing Adequately for Retirement?
Technical Report," mimeo, Princeton University, August 1992b.
Bernheim, B. Douglas. "W hat Determines Personal Saving? The Roles of Information and
Economic Literacy," in Tax Policy for Economic Growth in the 1990s. Washington, D.C.:
American Council for Capital Formation (forthcoming 1993).
Bernheim, B. Douglas, and John Karl Scholz. "Private Saving and Public Policy," mimeo,
Princeton University and the University of Wisconsin— Madison, September 1992a.
Bernheim, B. Douglas, and John Karl Scholz. "Premium Saving Accounts: A Proposal to
Improve Tax Incentives for Saving," mimeo, Princeton University and the University of
Wisconsin—Madison, September 1992b.
Bernheim, B. Douglas, and John B. Shoven. "Pension Funding and Saving," in Zvi Bodie,
John B. Shoven, and David A. Wise, eds., Pensions in the U.S. Economy. Chicago:
University of Chicago Press and NBER, 1988, pp. 85-111.
Boskin, Michael. "Taxation, Saving, and the Rate of Interest," Journal of Political Economy
(April 1978), pp. 3-27.
Cutler, David M., and Lawrence F. Katz. "Rising Inequality? Changes in the Distribution of
Income and Consumption in the 1980s," mimeo, Harvard University, January 1992.
Diamond, Peter A. "A Framework for Social Security Analysis," Journal of Public Economics
(December 1977), pp. 275-98.
Feenberg, Daniel R., and Jonathan Skinner. "Sources of IRA Saving," in Lawrence Summers,
ed., Tax Policy and the Economy, Cambridge, MA: MIT Press, 1989, pp. 25-46.
Gale, William G., and John Karl Scholz. "IRAs and Household Saving," mimeo, UCLA and
University of Wisconsin—Madison, 1992.
Hall, Robert. "Intertemporal Substitution in Consumption," Journal o f Political Economy 96,
1988, pp. 337-57.




19

REFERENCES (continued)

BUSINESS REVIEW

SEPTEMBER/OCTOBER 1993

Hamermesh, Daniel S. "Consumption During Retirement: The Missing Link in the LifeCycle," Review of Economics and Statistics (February 1984), pp. 1-7.
Hatsopoulos, George N., Paul R. Krugman, and James M. Poterba. Overconsumption:
The Challenge to U.S. Policy. Washington, D.C.: American Business Conference, 1989.
Horioka, Charles Y. "W hy Is Japan's Private Saving Rate So High?" in R. Sato and T. Negishi,
eds., Recent Developments in Japanese Economics. Tokyo: Harcourt Brace Jovanovich
Japan/Academic Press, 1988.
Joines, Douglas H., and James G. Manegold. "IRA and Saving: Evidence from a Panel of
Taxpayers," mimeo, U.S.C., 1991.
Kotlikoff, Laurence J., Avia Spivak, and Lawrence H. Summers. "The Adequacy of Saving,"
American Economic Review (December 1982), pp. 1056-69.
Meyer, Stephen A. "Saving and Demographics: Some International Comparisons," this
Business Review, March/April 1992, pp. 13-23.
Organization for Economic Cooperation and Development, Economic Outlook, 1992.
Shefrin, Hersh M., and Richard H. Thaler. "The Behavioral Life Cycle Hypothesis," Economic
Inquiry 26 (October 1988), pp. 609-43.
Summers, Lawrence. "Capital Taxation in a Life Cycle Growth Model," American
Economic Review (September 1981).
Summers, Lawrence. "Issues in National Savings Policy," National Bureau of Economic
Research Working Paper 1710, Cambridge, MA (September 1985).
Venti, Steven F., and David A. Wise. "Tax-Deferred Accounts, Constrained Choice and
Estimation of Individual Saving," Review of Economic Studies, LIII, 1986, pp. 579-601.
Venti, Steven F., and David A. Wise. "IRAs and Saving," in Martin Feldstein, ed., The Effects
of Taxation on Capital Accumulation. Chicago: University of Chicago Press and NBER,
1987, pp. 7-48.
Venti, Steven F., and David A. Wise. "Aging, Moving, and Housing Wealth," in David A.
Wise, ed., The Economics of Aging. Chicago: University of Chicago Press and NBER, 1989.
Venti, Steven F., and David A. Wise. "Have IRAs Increased U.S. Saving?: Evidence from
Consumer Expenditure Surveys," Quarterly Journal of Economics 105 (August 1990), pp.
661-98.
Venti, Steven F., and David A. Wise. "The Saving Effect of Tax-Deferred Retirement
Accounts: Evidence from SIPP," in B. Douglas Bernheim and John B. Shoven, eds.,
National Saving and Economic Performance. Chicago: University of Chicago Press and
NBER, 1991, pp. 103-28.

Digitized for
20 FRASER


FEDERAL RESERVE BANK OF PHILADELPHIA

Highways and Education:
The Road to Productivity?
Gerald A. Carlino*
rom 1948 to 1969, output per hour worked
grew at an average rate of 2.5 percent per year.
From 1969 to 1987, growth of labor productiv­
ity slowed to 1.1 percent per year. Economists
and policymakers have acknowledged that the
slowdown in productivity growth is one of the
major economic problems facing the United
States because sluggish productivity growth
means slower growth in our standard of living.
The decline in investment in public infrastruc­
ture and the decline in educational quality may
have played a role in this slowdown. Growth
of real government spending on nonmilitary

* Gerald A. Carlino is an economic adviser in the Regional
and Urban Section of the Philadelphia Fed's Research De­
partment.




public infrastructure declined from an annual
rate of 4.1 percent between 1948-69 to only 1.6
percent during 1969-87. There is also some
indication that educational quality may have
slipped over time as witnessed by the fact that
Scholastic Aptitude Test (SAT) scores have
been declining since the mid-1960s.1
The current Administration would like to
increase national productivity by, among other
things, increasing investment in public infra­
structure and by creating j ob training programs
to improve the quality of the work force. Would

'The data reported in this paragraph are taken from
Alicia H. Munnell, "Why Has Productivity Growth De­
clined? Productivity and Public Investment," New England
Economic Review, January/February 1990a, pp. 3-22.

21

BUSINESS REVIEW

programs such as these improve productivity
and ultimately the level of output?
Differences across states in investment in
public infrastructure and education provide
insight into the likely effects of national spend­
ing in these areas. A number of recent studies
have looked at the impact of public infrastruc­
ture and educational attainment on output at
the state and local levels. Studies have found
that increases in highway density and educa­
tional attainment improve a region's produc­
tivity and boost output. A recent study by
Carlino and Voith found that a 10 percent
increase in educational attainment of a state's
residents boosts its output by 8 percent, and a
10 percent increase in highway density increases
state output by 1.4 percent.2
REASONS PRODUCTIVITY
DIFFERS ACROSS STATES
Productivity measures the ratio of output to
inputs such as land, labor, and capital. If two
regions used the same quantities of inputs,
output would be greater in the more produc­
tive region. One region might have higher
productivity than another because the quality
of inputs is higher. Regional productivity de­
pends not only on the number of machines used
to produce an output but also on their age,
technical quality, and degree of utilization.
Regional productivity may also depend on the
scale at which production takes place within a
region's firms. As firms increase their size, they
can sometimes increase productivity by having
their workers specialize in particular tasks or
by using their capital equipment more effi­
ciently. These internal factors may vary from
one region to another and therefore may influ­
ence regional productivity.3 While these inter­
nal factors are an important source of produc-

2Gerald A. Carlino and Richard Voith, "Accounting for
Differences in Aggregate State Productivity," Regional Sci­
ence and Urban Economics, 2, December 1992, pp. 597-617.

Digitized for
22FRASER


SEPTEMBER/OCTOBER 1993

tivity differentials across regions, this article
focuses on public infrastructure and the quality
of the region's work force, factors that are
external to the firm but which influence produc­
tivity in a market or region. Before we look at
how much public infrastructure and work force
quality matter for productivity, we need to
understand other external factors that affect
productivity, such as a region's industry mix
and the degree of urbanization, so that we can
control for their effects.
Industry Mix. Regional differences in pro­
ductivity arise partly because individual re­
gions often specialize in the mix of goods or
services they produce. For instance, the grow­
ing of wheat and corn tends to be concentrated
in the Plains states. Because many of the states
in the Northeast and Midwest have historically
specialized in the production of manufactured
goods, this broad geographic area is commonly
referred to as the "industrial belt" or "indus­
trial core." Since some industries are more
productive than others, regions with a rela­
tively large concentration of the more produc­
tive industries will have greater overall pro­
ductivity than regions with a concentration of
the less productive industries.4
Urbanization Economies. Just as a region's
industry mix can influence its productivity, the

3These internal decisions by firms may be influenced by
external factors. For example, the size of a region's market
(external factor) may influence a regional firm's scale of
operation (internal factor).
4Baumol, Blackman, and Wolff looked at national pro­
ductivity growth by industry during the 1947-86 period.
They found that productivity growth does differ by indus­
try. They also reported that the traditional high-productivity-growth industries continued to perform well during the
1947-86 period, implying long-term differences in the level
of productivity across industries. See William J. Baumol,
Sue Anne Batey Blackman, and Edward N. Wolff, Productiv­
ity and American Leadership: The Long View (Cambridge, MA:
The MIT Press, 1989).

FEDERAL RESERVE BANK OF PHILADELPHIA

Highways and Education: The Road to Productivity?

percentage of a region's firms that are located
in metropolitan areas also affects its productiv­
ity. Metropolitan areas offer their firms access
to a common pool of trained labor, so that firms
not only share the cost of training new workers,
but any firm can vary its work force without
incurring lost productivity during training pe­
riods or by carrying idle workers. Metropoli­
tan locations also help firms by providing whole­
saling facilities that reduce the level of invento­
ries any one firm needs to keep on hand and by
providing access to accounting, data process­
ing, legal, financial, and other specialized busi­
ness services. Firms located in nonmetropolitan
areas would need to employ people who pro­
vide these specialized business services on a
full-time basis or else spend considerable time
and money bringing them from a distance when
they are needed. By locating in a metropolitan
area firms can contract for these on an asneeded basis.
Economists refer to the advantages offered
by metropolitan areas as urbanization econo­
mies. These urbanization economies should
increase the productivity of urban firms. Thus,
other things being equal, the more urbanized
regions should have greater productivity than
less urbanized regions. In other words, with
fewer inputs metropolitan firms can produce
the same level of goods and services as
nonmetropolitan firms.
Urbanization economies can increase firms'
productivity only up to a point. Urbanization
brings not only greater productivity but also
greater problems, such as congestion, that even­
tually balance or outweigh the efficiency gains
from urbanization. At some point, increases in
the number of people and firms residing in a
metropolitan area clog its roads and transpor­
tation network and raise the average time and
cost of transporting goods and commuting
either to work or to leisure activities. In addi­
tion, as a metropolitan area grows, its bound­
aries may spread out, which increases both the
time and distance of the average commute.



Gerald A. Carlino

When urban size becomes a hindrance rather
than a help, firms experience urbanization
diseconomies. Urbanization economies are
balanced by these diseconomies, suggesting
that there may be some optimal degree of
urbanization.
Individual firms that have incentives to ex­
ploit urbanization economies are guided by the
"invisible hand" of the marketplace to locate in
metropolitan areas. Local policymakers can
lend a hand to lessen the negative consequences
of congestion by providing public infrastruc­
ture, such as highways, airports, and mass
transit facilities, that link a region's labor and
product markets with one another and with
those of other regions.
Public Infrastructure. Some economists
believe that an increase in the capital stock of
the public sector leads directly to increases in
private sector output because public infrastruc­
ture is an essential input in the production of
private output.5 For example, driver produc­
tivity increases when a good highway system
allows truck drivers to avoid circuitous back
roads and to bring supplies to a firm and goods
to market more quickly. Similar arguments can
be made for the public provision of police and
fire protection, water supply facilities, airports,
and mass transit. An increase in the public
capital stock, like an increase in any factor of
production, directly increases private sector
output.6
Of course, some public sector spending may
actually substitute for private sector spending.
This would be the case if close substitutes for

5For a useful survey of the recent literature, see John A.
Tatom, "Should Government Spending on Capital Goods
Be Raised?" Review, Federal Reserve Bank of St. Louis,
March/April 1991, pp. 1-15; and Randall Eberts, "Public
Infrastructure and Regional Economic Development," Eco­
nomic Review, The Federal Reserve Bank of Cleveland (First
Quarter 1990a), pp.15-27.
6Munnell (1990a); see footnote 1 for complete citation.

23

BUSINESS REVIEW

publicly provided services are available from
the private sector.7 Public finance theory tells
us, however, that most public sector spending
should be for goods and services that would be
either not provided or underprovided if left to
the private sector. For example, private com­
panies could build roads and bridges and charge
tolls for using them. But private provision may
not be efficient. Although there is a large initial
fixed cost associated with construction of
bridges and highways, once constructed, the
ad d itional cost of one m ore vehicle on
uncongested roads is nearly zero. In this case,
economic efficiency requires setting a zero price
for use of uncongested roads. Thus, while it is
possible to exclude those unwilling to pay for
the use of infrastructure, such exclusion often is
inefficient.8 In such cases, the public sector
should provide infrastructure.
Labor-Force Characteristics. Policymakers
in state and local government in the U.S. have
a great deal of influence on the quality of the
work force because their policies affect the cost
and quality of the public education system.
Studies have shown that higher educational
attainment of a region's labor force is an impor­
tant contributor to higher regional productiv­
ity.9 These investments in human capital may

7Studies have found that labor and public capital are
complements in production, while there appears to be some
degree of substitutability between public capital and pri­
vate capital. See Jose da Silva Costa, Richard W. Ellson, and
Randolph C. Martin, "Public Capital, Regional Output and
Development: Some Empirical Evidence," Journal o f Re­
gional Science, 27 (1987), pp. 419-37; and Alicia H. Munnell,
"How Does Public Infrastructure Affect Regional Economic
Performance?" New England Economic Review, September/
October 1990b, pp. 11-33. Munnell finds that highways and
streets appear to be substitutes for private capital and
speculates that well-maintained roads reduce wear and
tear on commercial vehicles, lowering private sector main­
tenance and replacement of these vehicles.
8See Eberts (1990a; see footnote 5 for complete citation),
for a discussion of the public goods aspects of public inputs.




SEPTEMBER/OCTOBER 1993

lead to increased regional productivity because
education introduces a region's workers to
new techniques and skills. Since educational
attainment differs across regions, these differ­
ences can lead to variations in regional produc­
tivity.
THE EVIDENCE
Studies on regional productivity have tended
to limit their focus to specific aspects of re­
gional productivity. A number of studies since
the mid-1970s have looked at the impact of
urbanization economies on manufacturing pro­
ductivity at the regional level. These studies
have shown that manufacturing productivity
in general increases with metropolitan popula­
tion size (a proxy for urbanization economies),
at least over the observed ranges of metropoli­
tan sizes.10 Another group of regional produc­
tivity studies has examined the role of public
infrastructure in regional production, and most
studies find that greater investment in public
capital does raise regional productivity.11

9See, for example, Gerald A. Carlino and Edwin S. Mills,
"The Determinants of County Growth," Journal o f Regional
Science, 27 (1992), pp. 39-54.
10For a survey of this literature, see Ronald Moomaw,
"Spatial Productivity Variations in Manufacturing: A Criti­
cal Survey of Cross-Sectional Analysis," International Re­
gional Science Review, 8 (1983), pp. 1-22.
n See Randall Eberts, "Estimating the Contribution of
Urban Public Infrastructure to Regional Economic Growth,"
Working Paper 9004, Federal Reserve Bank of Cleveland
(May 1990b). While Eberts concentrates on the influence of
public capital on manufacturing output, an article by Alicia
Munnell and one by Teresa Garcia-Mila and Therese J.
McGuire extend the analysis of public infrastructure to
aggregate output at the state level. See Munnell (1990b;
footnote 7 has complete citation); and Teresa Garcia-Mila
and Therese J. McGuire, "The Contribution of Publicly
Provided Inputs to States' Economies," Regional Science and
Urban Economics, 22 (1992), pp.229-41. Both studies find that
public infrastructure has positive effects on aggregate pro­
ductivity at the state level.

FEDERAL RESERVE BANK OF PHILADELPHIA

Highways and Education: The Road to Productivity?

The examination of each of these factors in
isolation can result in misleading conclusions.
For example, the contribution of public infra­
structure to regional productivity may be over­
stated if the other factors thought to influence
regional productivity are not taken into consid­
eration. The clustering of firms in metropolitan
areas creates urbanization economies, which,
in turn, increases a region's overall productiv­
ity and output. More output leads to increased
tax revenue for state and local governments.
Some of the increased tax revenue may be used
to supply public infrastructure. Perhaps it is
urbanization economies that largely contribute
to regional productivity, and public infrastruc­
ture contributes to a much lesser extent or not
at all. Since increased urbanization economies
lead to more output, which, in turn, leads to
more public infrastructure, studies that look at
the role of public infrastructure on regional
productivity but fail to control for urbanization
economies run the risk of overstating the rela­
tive importance of public capital.12
The Carlino and Voith study provides a
more comprehensive view of the factors affect­
ing state productivity by considering the rela­
tive importance of industry mix, urbanization
economies, public infrastructure, and labor
quality on aggregate production at the state
level during the 1967-86 period (see Appendix,
page 30).13

12An unresolved issue is whether public capital pre­
cedes private capital formation or vice-versa. There is
evidence that the formation of public capital and private
capital is a simultaneous process. See Eberts (1990a; foot­
note 5 has complete citation).
13Carlino and Voith (1992; see footnote 2) used multiple
regression analysis to examine the relative importance of
industry mix, labor-force quality, urbanization economies,
and infrastructure on state aggregate productivity. One
problem with analyzing the results from a multiple regres­
sion analysis is that the variables are generally measured in
different units. For example, educational attainment is
measured in years, and public infrastructure is measured in




Gerald A. Carlino

Industry Mix. Carlino and Voith measured
industry mix by the share of state output attrib­
utable to each of the nine major industry group­
ings.14 By including these industry-mix vari­
ables, their study controlled for industrial struc­
ture differences across states, which helped to
isolate the effects of the other variables thought
to have independent effects on state productiv­
ity. Carlino and Voith found that state produc­
tivity varies a lot, running from about 50 per­
cent above the national average in Delaware to
about 35 percent below average in Wyoming.
They also found that controlling for industry
mix alone explains about 26 percent of the
variation (see Industry Mix Is an Important Com­
ponent o f a Region's Aggregate Productivity).
Urbanization Economies. The Carlino and
Voith study used the percent of a state's popu­
lation that is metropolitan to capture the effects
of urbanization economies. The percent of the
population living in metropolitan areas varied
widely across states in 1984; for example, it is as
low as 14.7 percent in Wyoming and as high as
100 percent in New Jersey.15The positive effects

terms of highway density. To facilitate the comparison of the
effects of different variables, we must standardize our find­
ings. A common approach couches relationships in per­
centage terms—the percent change in one variable associ­
ated with the percent change in another. This unitless
measure is known as an elasticity. The elasticity for state
output tells us the percent change in state output given a
percentage change in any of the explanatory variables,
while holding all other explanatory variables constant.
14These groupings are agriculture; mining; construction;
manufacturing; transportation, communication, and public
utilities; trade (wholesale and retail combined); finance,
insurance, and real estate (FIRE); services; and government.
Since the industry shares of state output sum to one, it is
necessary to drop the percentage share of one of the indus­
tries. Although agriculture is the excluded industry in the
Carlino and Voith study, the study could just as easily have
excluded any one of the other industries.
15Every county in New Jersey is part of a metropolitan
area even though large parts of some counties are rural.

25

Industry Mix Is an Important Component of a Region's Aggregate Productivity

BUSINESS REVIEW

SEPTEMBER/OCTOBER 1993

The estimates of total factor productivity from the Carlino/Voith study can be used to
compare aggregate productivity across states by looking at the ratio of productivity in a state
relative to productivity averaged across all states. If productivity in a state is equal to the
national average, the ratio would equal one. If the state is more productive than the average
state, the ratio would be greater than one. And the ratio is less than one if the state is less
productive than the average state.
State productivity varies from about 50 percent above the national average (48-state average)
in Delaware to about 35 percent below the national average in Wyoming (see Table). Even with
the exclusion of Delaware, there is a 58 percent differential between Rhode Island, the second
most productive state, and Wyoming, the least productive state. But controlling for industry
mix alters the picture substantially.
Industry Mix. Total productivity was recalculated for each state, controlling for industry
mix differences across states by assigning the national industry mix to each state. Controlling
for industrial structure reduces the differential in total productivity across states by 26 percent.
The differential in state productivity runs from about 43 percent above the national average
(compared with 50 percent above average before standardization) to 19 percent below the
national average (compared with 35 percent below before standardization). Of the 16 states in
the top one-third of the productivity distribution before standardization, 13 states remain in the
top one-third after standardization. Indiana, Maine, and Massachusetts, which were in the top
one-third before standardization, moved to the middle third after standardization. Three
states, Louisiana, Oklahoma, and New Mexico, were in the bottom one-third before standard­
ization but moved to the top one-third after standardization.
Wyoming is an interesting example of how industry mix can affect a state's productivity in
that it moves from being 35 percent below the U.S. before standardization to just about at the
national average after controlling for industrial structure. A relatively large portion of total
employment in Wyoming is in the extractive industries, especially oil and gas. Mining
employment in Wyoming accounted for 22 percent of total employment in 1980, compared
with only one percent nationally. Wyoming also tends to be much less manufacturing oriented.
In 1980, only 6 percent of total employment in Wyoming was accounted for by manufacturing,
compared with 28 percent nationally. One recent study shows that while productivity in the
mining industry fell dramatically during the period 1947-86, it improved slightly in
manufacturing.3

aWilliam J. Baumol, Sue Anne Batey Blackman, and Edward N. Wolff, Productivity and American Leadership:
The Long View (Cambridge, MA: MIT Press, 1989).

Digitized for
26FRASER


FEDERAL RESERVE BANK OF PHILADELPHIA

Highways and Education: The Road to Productivity?

Gerald A. Carlino

Aggregate Productivity Differences Across States3
Total

Controlling for
Industry Mix

Total

Controlling for
Industry Mix

1

Delaware

1.5002

1 1.4338

25

Nevada

1.0210

42 0.9058

2

Rhode Island

1.2282

2 1.1886

26

Arkansas

1.0178

19 1.0149

3

South Carolina

1.2081

3 1.883

27

Maryland

1.0177

31 0.9660

4

Georgia

1.1833

12 1.0603

28

Arizona

0.9953

36 0.9350

5

Connecticut

1.1685

6 1.1210

29

Oregon

0.9867

39 0.9144

6

New Hampshire

1.1456

10 1.0723

30

Virginia

0.9751

26 0.9908

7

Tennessee

1.1230

13 1.0595

31

Iowa

0.9687

25 0.9922

8

Vermont

1.1156

14 1.0591

32

Mississippi

0.9653

20 1.0127

9

Indiana

1.1061

17 1.0481

33

Colorado

0.9364

40 0.9102

10

West Virginia

1.1007

5 1.1609

34

Florida

0.9343

46 0.8332

11

Missouri

1.0949

29 0.9780

35

Washington

0.9289

44 0.8700

12

North Carolina

1.0913

11 1.0603

36

Kansas

0.9274

32 0.9642

13

Alabama

1.0868

9 1.0730

37

Nebraska

0.9250

38 0.9184

14

Massachusetts

1.0864

24 0.9997

38

Idaho

0.9138

41 0.9089

15

Michigan

1.0832

16 1.0506

39

Oklahoma

0.9061

7 1.1194

16

Maine

1.0830

21

1.0075

40

Utah

0.9022

43 0.8881

17

Illinois

1.0788

27 0.9870

41

Texas

0.8433

28 0.9816

18

Ohio

1.0662

22 1.0005

42

North Dakota

0.8409

35 0.9426

19

Wisconsin

1.0515

18 1.0324

43

California

0.8285

48 0.8090

20

New York

1.0450

34 0.9528

44

Louisiana

0.8236

4 1.1647

21

Pennsylvania

1.0386

33 0.9533

45

South Dakota

0.8143

45 0.8626

22

New Jersey

1.0381

37 0.9350

46

New Mexico

0.7989

15 1.0531

23

Minnesota

1.0337

30 0.9765

47

Montana

0.7744

47 0.8296

24

Kentucky

1.027

8 1.0880

48

Wyoming

0.6457

23 0.9998

aIndex represents ratio of aggregate productivity in each state to the national average.




27

BUSINESS REVIEW

SEPTEMBER/OCTOBER 1993

of increased urbanization make up one side of
the urban size ledger. The negative effects of
congestion brought on by increased urbaniza­
tion make up the other. Thus, Carlino and
Voith allowed for the fact that increasing the
degree of urbanization would increase pro­
ductivity up to a point, after which productiv­
ity would decrease.16 Both forces influence
productivity: increased urbanization encour­
ages growth, and increased congestion dis­
courages it. Carlino and Voith found that the
positive effects of urbanization economies are
greatest when roughly half of a state's popula­
tion is metropolitan.17
Infrastructure. A state can mitigate the
effects of congestion by building and main­
taining streets and highways. The Carlino and
Voith study employed highway density (high­
way miles per square mile of land area in a
state) as a proxy for state infrastructure, partly
because of the relative importance of high­
ways and partly because data for the other
categories of public capital are generally not
available.18 The study found that state produc­

tivity responds to the availability of a highway
network. A 10 percent increase in a state's
highway density leads, on average, to a 1.4
percent increase in total output. The Carlino
and Voith study corroborates the findings re­
ported in several recent studies in terms of the
importance of infrastructure spending on state
output. One study, by Garcia-M ila and
McGuire, employed annual expenditures on
highways by state and local governments dur­
ing 1969-83 as a measure of public sector capi­
tal. The study found that a 10 percent increase
in highway spending results in a 0.7 to 1.7
percent increase in aggregate state output.19 A
study by Munnell, using a broader measure of
infrastructure than the one employed by
Carlino and Voith, found that a 10 percent
increase in infrastructure led to a 1.5 percent
increase in aggregate state output during the
1970-86 period.20 The similarity of the findings
among the three studies supports the concept
of public infrastructure spending as a public
policy instrument for fostering productivity
growth at the state level.21

16T o capture the effects of congestion Carlino and Voith
took the percent of a state's population that is metropolitan
and squared it. This follows William BaumoTs reasoning
that if each resident of a metropolitan area imposes exter­
nal costs on every other, and if the magnitude of the cost
borne by each resident is roughly proportional to a metro­
politan area's population size, then since these costs are
borne by each of R residents involved, the total external
cost will increase not with R but with R2. See William J.
Baumol, "Macroeconomics of Unbalanced Growth: The
Anatomy of Urban Crisis," American Economic Review,
Vol.57 (1967), pp. 415-26.

Most of this infrastructure consists of assets owned by state
and local governments. The largest single item is highways
and streets, which account for 39 percent of total state and
local wealth. See Munnell (1990b; footnote 7 has complete
citation).

17Of course, factors other than percent of a state's popu­
lation that is metropolitan can influence the urbanization
economies states offer. For example, urbanization econo­
mies may spill over state boundaries so that states that are
not highly urbanized may benefit from urbanization econo­
mies if they are near highly urbanized states.
18In 1988 nonmilitary infrastructure amounted to $2
trillion, compared with $4.4 trillion in private capital.




19Garcia-Mila and McGuire (1992; footnote 11 has com­
plete citation).
20Munnell (1990b; footnote 7 has complete citation).
Munnell found that an additional dollar of public infra­
structure spending yielded the same increase in aggregate
state output as an additional dollar spent on private capital.
Munnell used the stock of state and local public capital,
which includes highways and streets, water and sewer
systems, buildings (schools, hospitals, etc.), and equipment.
The results of this study are somewhat controversial. See
John A. Tatom, "Public Capital and Private Sector Perfor­
mance," Review, Federal Reserve Bank of St. Louis, M ay/
June 1991, pp. 3-15; and Alicia H. Munnell, "Infrastructure
Investment and Economic Growth," Journal o f Economic
Perspectives, 16, Fall 1992, pp. 189-198.

FEDERAL RESERVE BANK OF PHILADELPHIA

Highways and Education: The Road to Productivity?

Gerald A. Carlino

Labor-Force Characteristics. Differences in
labor-force composition—education, experi­
ence, degree of unionization—across states can
result in differences in aggregate productivity.
The Carlino and Voith study uses educational
attainment, defined as the percent of a state's
population that is 25 years old and over with 12
or more years of schooling, as its measure of
labor-force quality. The percent of a state's 25and-over population with at least a high school
diploma varies widely across the United States;
for example, in 1980 it was as low as 53 percent
in Kentucky and as high as 80 percent in Ari­
zona. Carlino and Voith's results indicate that
a 10 percent increase in educational attainment
leads, on average, to an 8 percent increase in

aggregate output.*22 This finding suggests that
education is an important public policy instru­
ment for promoting productivity growth at the
state level.23

21The magnitude of the effect of public infrastructure on
state level output is about half as large as that found for the
national economy. For example, Aschauer found that a 10
percent increase in the stock of public capital led to a 3.9
percent increase in national output. See David A. Aschauer,
"Is Public Expenditure Productive?" Journal o f Monetary
Economics, 23, March 1989, pp. 177-200. When one state
adds to its stock of public infrastructure, this increased
investment most likely has a beneficial effect on the output
of neighboring states. For example, the opening of Interstate
476 in Pennsylvania in 1992 not only made Pennsylvania's
workers more productive, but it may have improved the
productivity of workers in Delaware and New Jersey as
well. For a general critique of Aschauer's findings, see
Laura Rubin, "Productivity and the Public Capital Stock:

Another Look," Working Paper No. 118, Board of Gover­
nors of the Federal Reserve System, May 1991.




CONCLUSION
The research summarized in this article sup­
ports the view that increased infrastructure
spending and greater educational attainment
do improve productivity and ultimately the
level of output. Further research should help
determine the relative effects of additional
spending on infrastructure and education. But
the findings so far suggest that state govern­
ments should pay close attention to investment
in public capital and to the level of educational
attainment of their workers.

22Of course, more productive workers may place a higher
value on educational attainment. To some extent, therefore,
productivity and educational attainment may be a simulta­
neous process.
23Factors other than those discussed here could affect
state productivity, including state policies and regulations,
the degree of unionization, research and development spend­
ing, and technical progress. While these factors may deter­
mine differences in state productivity, few, if any, data are
available to determine the relative importance of these
omitted variables.

29

APPENDIX

BUSINESS REVIEW

SEPTEMBER/OCTOBER 1993

A state's output of goods and services depends on the quantities of inputs, such as capital
and labor, and on the productivity of those inputs. The relationship among output, inputs,
and productivity is given in the following production function:
Q = AF(K, L)
Accordingly, the amount of real output, Q, that a state can produce during some period,
such as a year, depends on the size of its capital stock, K, and the number of hours worked,
L. The symbol F is a function, or equation, relating output to capital and labor inputs. The
symbol A measures the overall effectiveness with which a state uses its capital and labor
resources. The symbol A is therefore referred to as a measure of total factor productivity. If
two states used the same levels of capital and labor, the more productive state would have a
larger A term and would therefore produce more output than the state with a lower A term.
While some studies have treated the various productivity factors as inputs in the produc­
tion function, the Carlino/Voith study treated them as affecting the efficiency parameter, A.
Specifically, the value of A depends on industry mix, urbanization economies, public capital,
and the quality of labor. This means that the various productivity factors augment private
sector use of labor and capital. In this case, an increase in the level of public capital increases
the efficiency of both private capital and labor.
The Empirical Model. Empirical analysis of state productivity has had to deal with an
important data problem, namely, data on the stock of capital at the state level are not available.
Fortunately, a production function technique has been developed that permits the estimation
of productivity without the need for data on the capital stock.3 The technique involves
estimating a wage equation. It is assumed that workers are paid according to their
productivity (that is, there is perfect competition in and across local labor markets), and
therefore wages and the demand for labor reflect the differentials in productivity across states.
Under these conditions, the following wage equation is derived from the aggregate produc­
tion function:

where
W.( = Annual aggregate real wage bill divided by number of employees in state i for
time t.
S..t = The real output share of the j-th one-digit industry (mining; construction; manufactur­
ing; transportation, communication, and public utilities; wholesale and retail trade;
finance, insurance, & real estate; services; and government) in state i for time t.
P. = For each year, the percent of state i's population living in metropolitan areas in 1970
or 1980 (whichever is closest) based on 1983 metropolitan area definitions.
I.
= Total primary Federal-Aid Highway System miles per square mile of land
area in state i for 1980.
E. = Educational attainment (percent of the population 25 years old and over with 12 or
more years) in i in 1980.

aSee Gerald A.Carlino, "Increasing Returns to Scale in Metropolitan Manufacturing," Journal of
Regional Science, 19,1979, pp. 363-73.




FEDERAL RESERVE BANK OF PHILADELPHIA

APPENDIX (continued)

Highways and Education: The Road to Productivity?

Gerald A. Carlino

T
Zt

= Technical progress, represented by a time index.
= Dummy variable to capture the effects of the energy shock years; Z( = 1 if t = 1973
to 1978; and 0 otherwise.
U = Union membership as a percent of employees in nonagricultural establishments in
i for 1970.
Q = Real gross state product in state i at time t.
Lu = Aggregate employment in state i at time t.

The findings reported in the text of this article are based on a random-effects estimation
of a pooled cross-section time series model for the 48 contiguous states for the period 196786 (providing 960 observations).13 While a wage equation was estimated, we obtained the
effects of industry mix, urbanization economies, public infrastructure, and labor force
quality on output indirectly by transforming the appropriate estimated coefficients of the
wage equation.0

bThe estimated coefficients for industry mix, urbanization economies, public capital, and labor quality
capture the direct effect of these variables on labor productivity. There may also be important indirect
effects that are not captured by the estimates. For example, states with high educational attainment may
also attract the more productive industries.
°Let a krepresent the output effect of the k-th productivity variable. Then the output effect is calculated
indirectly as a k = (3 / p, where p = 0 -1. For details see Gerald A. Carlino and Richard Voith, "Accounting
for Differences in Aggregate State Productivity," Regional Science and Urban Economics, 22,1992, pp. 597617.




31

FEDERAL
RESERVE BANKOF
PHILADELPHIA
BUSINESS REVIEW Ten Independence Mall, Philadelphia, PA 19106-1574