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For release on delivery
2 45 p m local tune (8 45 a m EST)
November 7, 1997

"Problems of Price Measurement"
Remarks by
Alan Greenspan
Chairman
Board of Governors of the Federal Reserve System
at the
Center for Financial Studies
Frankfurt, Germany
November 7, 1997

The remarkable progress that has been made by virtually all of the major industrial
countries in achieving low rates of inflation in recent years has brought into sharper focus the
issue of price measurement As we move closer to price stability, the necessity of measurmg
prices accurately has become an especial challenge Biases of a few tenths in annual inflation
rates do not matter when inflation is high They do matter when, as now, a debate has
emerged over whether our economies are moving toward price deflation
In today's advanced economies, allocative decisions are primarily made not by
governments but by markets, and the central guide to the efficient allocation of resources in a
market economy is prices Prices are the signals through which tastes and technology affect
the decisions of consumers and producers, directing resources toward their highest valued use
Of course, this signaling process would work with or without government statistical agencies
that measure individual and aggregate price levels, and in this sense, price measurement
probably is not fundamental for the overall efficiency of the market economy Indeed, vibrant
market economies existed long before government agencies were established to measure
prices
Nonetheless, in a modern monetary economy, accurate price measurement is of
considerable importance, increasingly so for central banks whose mandate is to maintain
financial stability Accurate price measures are necessary for understanding economic
developments, not only involving inflation, but also involving real output and productivity If
the general price level is estimated to be rising more rapidly than is in fact the case, then we
are simultaneously understating growth in real output and productivity Real incomes and
living standards are rising faster than our published data suggest Under these circumstances,

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policymakers must be cognizant of the shortcomings of our published price indexes to avoid
misguided actions that will provoke unintended consequences

Clearly, central bankers need

to be conscious of the problems of price measurement as we gauge policies designed to
promote price stability and maximum sustainable economic growth Moreover, many
economic transactions, both private and public, are explicitly tied to movements in some
published price index, most commonly a consumer price index, and some transactions that are
not explicitly tied to a published price index may nevertheless take such an index into account
less formally

If the price index is not accurately measuring what the participants in such

transactions believe it is measuring, then economic transactions will be skewed
The measured price indexes have played an especially prominent role in Germany, both in
terms of public perceptions of inflation performance and as a guide for policymakers

The

Bundesbank's long-standing commitment to price stability and the public's support for that
commitment derive at least to some extent from Germany's experiences with hyperinflation
earlier this century

Given this experience with the devastation that such inflation can bring to

the economy and to people's lives, it comes as no surprise that your public and your
policymakers give such careful scrutiny to the available measures of inflation

Germany has a

reputation for special vigilance in guarding the stability of the price level, and has achieved an
admirable record of success in maintaining low inflation over the postwar period From the
standpoint of monetary policy, this very success makes accurate price measurement all the
more important

When measured inflation is high, we can be confident that the proper

direction of monetary policy is to bring inflation lower But when measured inflation is low,

the proper direction of monetary policy, as I indicated, could depend crucially on the accuracy
of those measurements
The importance of accurate price measurement was particularly apparent during
unification, when it became necessary to gauge productivity in East and West Germany on a
comparable basis Initial estimates of East German productivity relative to that of the West
were considerably higher than later, more accurate estimates showed to be the case These
differences, we are told, owed largely to the difficulties in adjusting the prices of East German
products to take into account that they were, on average, of lower quality than the equivalent
items produced in the West
In thinking about the problems of price measurement, a distinction must be made between
the measurement of individual prices, on the one hand, and the aggregation of those prices
into indexes of the overall price level on the other The notion of what we mean by a general
price level—or more relevantly, its change-is never unambiguously defined

Moreover, in

practice, aggregation can be complicated because standard price indexes frequently assume that
individuals and businesses purchase the same basket of goods and services over time-whereas,
in fact, people substitute some goods for others when relative prices change and as new goods
are introduced How one aggregates individual prices, of course, depends on the purpose of
the measure

Still, the problems of aggregation are well understood by economists, and

workable solutions are within reach Many countries have made progress in utilizing
aggregation formulas that do take into account product substitutions, and further progress in
this area seems likely in the years ahead

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It is the measurement of individual prices, not the aggregation of those prices, that is so
difficult conceptually

At first glance, observing and measuring prices might not appear

especially daunting After all, prices are at the center of virtually all economic transactions
But, in fact, the problem is extraordinarily complex To be sure, the nominal value-in dollars
or deutsche marks, for example—of most transactions is unambiguously exact, and, at least in
principle, is amenable to highly accurate estimation by our statistical agencies But dividing
that nominal value change into components representing changes in real quantity versus price
requires that one define a unit of output that is to remain constant over tune Defining such a
constant-quality unit of output is the central conceptual difficulty in price measurement
Such a definition may be clear for unalloyed aluminium ingot of 99 7 percent purity for the
vast proportion of transactions, consequently, its price can be compared over time with a
degree of precision adequate for virtually all producers and consumers of aluminium ingot
Similarly, the prices of a ton of cold rolled steel sheet, or of a linear meter of cotton broad
woven fabric, can be reasonably compared over a period of years
But when the characteristics of products and services are changing rapidly, defining the
unit of output, and thereby adjusting an item's price for improvements in quality, can be
exceptionally difficult

These problems are becoming pervasive in modern economies as

service prices, which are generally more difficult to measure, become more prominent in
aggregate price measures One does not have to look to the most advanced technology to
recognize the difficulties that are faced

To take just a few examples, automobile tires,

refrigerators, winter jackets, and tennis rackets have all changed in ways that make them
surprisingly hard to compare to their counterparts of twenty or thirty years ago

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The continual introduction of new goods and services onto the markets creates special
challenges for price measurement In some cases, a new good may best be viewed as an
unproved version of an old good But, in many cases, new products may deliver services that
simply were not available before When personal computers were first introduced, the
benefits they brought households in terms of word processing services, financial calculations,
organizational assistance, and the like, were truly unique The introduction of heart bypass
operations literally prolonged many lives by decades And, further in the past, think of the
revolutionary changes that automobile ownership, or jet travel, brought to people's lives In
theory, economists understand how to value such innovations, in practice, it is an enormous
challenge to construct such an estimate with any precision
The area of medical care, where technology is changing in ways that make techniques of
only a decade ago seem archaic, provides some particularly striking illustrations of the
difficulties involved in measuring quality-adjusted prices Cures and preventive treatments
have become available for previously untreatable diseases Medical advances have led to new
treatments that are more effective and that have increased the speed and comfort of recovery
In an area with such rapid technological change, what is the appropriate unit of output? Is it a
procedure, a treatment, or a cure? How does one value the benefit to the patient when a
condition that once required a complicated operation and a lengthy stay in the hospital now can
be easily treated on an outpatient basis?
Although there is considerable uncertainty, the pace of change and the shift toward output
that is difficult to measure are more likely to quicken than to slow down How, then, will we
measure inflation in the future if our measurement techniques become increasingly obsolete?

6
We must keep in mind that, difficult as the problem seems, consistently measured prices do
exist in principle Embodied in all products is some unit of output, and hence of price, that is
recognizable to those who buy and sell the product if not to the outside observer A company
that pays a sum of money for computer software knows what it is buying, and at least has an
idea about its value relative to software it has purchased in the past, and relative to other
possible uses for that sum of money in the present
Furthermore, so long as people continue to exchange nominal interest rate debt instruments
and contract for future payments in terms of dollars or other currencies, there must be a
presumption about the future purchasing power of money no matter how complex individual
products become Market participants do have a sense of the aggregate price level and how
they expect it to change over time, and these views must be embedded in the value of financial
assets
The emergence of inflation-indexed bonds, while providing us with useful information,
does not solve the problem of ascertaining an economically meaningful measure of the general
price level By necessity, the total return on indexed bonds must be tied to forecasts of
specific published price indexes, which may or may not reflect the market's judgment of the
future purchasing power of money To the extent they do not, of course, the implicit real
mterest rate is biased in the opposite direction Moreover, we are, as yet, unable to separate
compensation for inflation risk from compensation for expected inflation
Eventually, financial markets may develop the instruments and associated analytical
techniques for unearthing these implicit changes in the price level with some precision

In

those circumstances, then—at least for purposes of monetary policy-these measures could

obviate the more traditional approaches to aggregate price measurement now employed They
may help us understand, for example, whether markets perceive the true change in aggregate
prices to reflect fixed or variable weight indexes of the components, or whether arithmetic or
logarithmic weighting of the components is more appropriate
But, for the foreseeable future, we shall have to rely on our statistical agencies to produce
the price data necessary to assess economic performance and to make economic policy In that
regard, assuming further advances in economic science and provided that our statistical
agencies receive adequate resources, procedures should continue to improve To be sure,
progress will not be easy, for estimating the value of quality improvements is a painstaking
process

It must be done methodically, item by item But progress can be made

One improvement that has been made in recent years is a better ability to capture quality
differences by pricing the underlying characteristics of complex products

With an

increasingly wide range of product variants available to the public, product characteristics are
now bundled together in an enormous variety of combinations A "personal computer" is, in
actuality, an amalgamation of computing speed, memory, networking capability, graphics
capability, and so on Computer manufacturers are moving toward build-to-order systems, in
which any combination of these specifications and peripheral equipment is available to each
individual buyer

Other examples abound Advancements in computer-assisted design have

reduced the costs of producing multiple varieties of small machine tools The variety of
commercial aircraft is much larger now than it was 20 years ago And in services, witness the
plethora of products now available from financial institutions, which have allowed a more
complete disentangling and exchange of economic risks across participants around the world

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Although hard data are scarce, there can be little doubt that products are tailor-made for the
buyer to a larger extent than ever Gone are the days when Henry Ford could say he would
sell a car of any color "so long as it's black "
In such an environment, when product characteristics are bundled together in so many
different combinations, defining the unit of output means unbundling these characteristics, and
pricing each of them separately

The so-called hedonic technique is designed to do precisely

that This technique associates changes in a product's price with changes in product
characteristics It therefore allows a quality comparison when new products with improved
characteristics are introduced
Not surprisingly, one area in which this approach has been especially useful is in computer
technology

In the United States, prior to the mid-1980s computer prices simply were held

constant in the national accounts Now, with the introduction of hedonic techniques, the
accounts show computer prices declining at double-digit rates, surely a more accurate estimate
of the true quality-adjusted price change The few other countries that have introduced these
techniques-France being the most recent-show computer prices declining much more rapidly
than in the majority of countries that have not yet done so
But hedonics are by no means a panacea First of all, this technique obviously will be of
no use in valuing the quality of an entirely new product that has fundamentally different
characteristics from its predecessors

The benefits of cellular telephones, and the value they

provide in terms of making calls from any location, cannot be measured from an examination
of the attributes of standard telephones

In addition, the measured characteristics may only be proxies for the overall performance
that consumers ultimately value In the case of computers, the buyer ultimately cares about
the quality of services that computer will provide—word processing capabilities, database
services, high-speed calculations, and so on But, in many cases, the number of message
instructions per second and the other easily measured characteristics may not be a wholly
adequate proxy for the computer services that the buyer values In these circumstances, the
right approach, ultimately, may be to move toward directly pricing the services we obtain
from our computers—that is, word processing services, database management services, and so
on-rather than pricing separately the hardware and software
The issues surrounding the appropriate measurement of computer prices also illustrate
some of the difficulties of valuing goods and services when there are significant interactions
among users of the products New generations of computers sometimes require software that
is incompatible with previous generations, and some users who have no need for the improved
computing power nevertheless may feel compelled to purchase the new technology because
they need to remain compatible with the bulk of users who are at the frontier

Even if our

techniques allow us to accurately measure consumers' valuation of the increased speed and
power of the new generation of computer, we may miss the negative influence on some
consumers of this incompatibility

Therefore, even in the case of personal computers, where

we have made such great strides in measuring quality changes, I suspect that important
phenomena still may not be adequately captured by our published price indexes
Despite the advances in price measurement that have been made over the years, there
remains considerable room for improvement In the United States, a group of experts

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empaneled by the Senate Finance Committee--the Boskin commission-concluded that the
consumer price index has overstated changes in the cost of living by roughly one percentage
point per annum in recent years About half of this bias owed to inadequate adjustment for
quality improvement and the introduction of new goods, and about half reflected the manner in
which the individual prices were aggregated Researchers at the Federal Reserve and
elsewhere have come up with similar figures

Although the estimates of bias owing to

inadequate adjustment for quality improvements surely are the most uncertain aspect of this
calculation, the preponderance of evidence is that, on average, such a bias in quality
adjustment does exist
The Boskin commission, along with most other estimates of bias in the U S CPI, have
taken a microstatistical approach, estimating separately the magnitude of each category of
potential bias Recent work by staff economists at the Federal Reserve Board has added
corroborating evidence of price mismeasurement, using a macroeconomic approach that is
essentially independent of the microstatistical exercises Specifically, employing disaggregated
data from the national income and product accounts, this research finds that the measured
growth of real output and productivity in the service sector is implausibly weak, given that the
return to owners of businesses in that sector apparently has been well-maintained

Indeed, the

published data indicate that the level of output per hour in a number of service-producing
industries has been falling for more than two decades It is simply not credible that firms in
these industries have been becoming less and less efficient for more than twenty years
more reasonable is the view that prices have been mismeasured, and that the true
quality-adjusted prices have been rising more slowly than the published price indexes

Much

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Properly measured, output and productivity trends in these service industries might be
considerably stronger than suggested by the published data Assuming, for example, no
change in productivity for these industries would imply a price bias consistent with the Boskin
commission findings
Of course, the United States is not the only country that faces challenges in constructing an
accurate measure of inflation

Other countries-Germany among them-confront similar issues

In a recent survey of consumer price indexes in its member countries, the OECD found that
most countries felt that measurement bias was smaller in magnitude in their own countries than
in the United States Certainly regarding quality adjustment, however, I doubt that this is
generally the case Many countries' responses were prepared by the countries' statistical
agencies, which tend to take a somewhat more sanguine view of the adequacy of the existing
price statistics than do outside economists But, in any case, the OECD survey did indicate
that many countries reported that measurement bias was a concern, and that most countries do
not adequately adjust their statistics for quality improvements Indeed, as I noted previously,
most European countries still have yet to adopt the most up-to-date techniques for measuring
computer prices in their national accounts As the OECD survey recognized, the challenges
presented by rapid technological advances have affected all of us~not just the United States
Thus, potential sources of measurement bias should be seriously examined in all countries
Indeed, issues of price measurement may be especially important for the European
countries entering into monetary union For a region with a single monetary policy, a single,
consistently estimated measure of inflation is necessary to gauge the region's economic
performance

Toward that end, as you know, Eurostat publishes harmonized indexes of

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consumer prices that are constructed using a common basket of goods and services for each
EU member state and using similar statistical methodology These measures should go a long
way toward providing a conceptually sound basis for judging convergence of EU member
states in the selection of countries to participate in monetary union Subsequent to monetary
union, harmonized consumer prices can be used as the best available measure of inflation in
the Euro area
However, as it now stands, the harmonized measures do not contain a broad coverage of
consumer services Most notably, the costs of owner-occupied housing—a sizable share of
consumer expenditures—are excluded from the harmonized indexes In the United States, for
example, the CPI calculated on this harmonized basis would have increased three or four
tenths of a percentage point more slowly than the published CPI, on average, over the past few
years, largely because prices of owner-occupied housing have been rising more rapidly than
the other components

Arguably, the published index, with broader coverage, is more

relevant to assessing inflation trends in the United States than would be the harmonized index
As long as relative prices can and do diverge across countries, the harmonized indexes need to
contain as broad a range of items as is practical
As monetary union proceeds, then, it would be to the advantage of monetary authorities in
the Euro area to have a consistent measure of inflation defined over a broad basket of goods
and services that is measured according to established statistical methods Most useful would
be for the member countries to continue the harmonization process until the national statistical
agencies are truly working on a consistent basis Indeed, measuring prices consistently across
countries could be an important step toward making price measurement more accurate

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everywhere, if harmonization results in each country's best practices being adopted throughout
the monetary union Moreover, different prices of the same tradable good across the
community might signal inefficiencies of distribution which were not evident from other
sources
Harmonization of CPIs in Europe is just one of many examples demonstrating why price
measurement techniques cannot be static With innovation constantly leading to new products,
greater variety, and higher quality, the statistical agencies must work ever harder just to stay
in place A government official in the United States once compared a nation's statistical
system to a tailor, measuring the economy much as a tailor measures a person for a suit of
clothes-with the difference that, unlike the tailor, the person we are measuring is running
while we try to measure him The only way the system can succeed, he said, is to be just as
fast and twice as agile That is the challenge that lies ahead, and it is, indeed, a large one
There are, however, reasons for optimism The information revolution, which lies behind
so much of the rapid technological change that makes prices difficult to measure, may also
play an important role in helping our statistical agencies acquire the necessary speed and
agility to better capture the changes taking place in our economies For example, computers
might some day allow our statistical agencies to tap into a great many economic transactions
on a nearly real-time basis Utilizing data from store checkout scanners, which the United
States is now investigating, may be an important first step in that direction But the
possibilities offered by information technology for the improvement of price measurement may
turn out to be much broader in scope Just as it is difficult to predict the ways in which

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technology will change our consumption over time, so is it difficult to predict how economic
and statistical science will make creative use of the improved technology
Such advances must be taken to ensure that our economic statistics remain adequate to
support the public policy decisions that must be made If the challenge for our statistical
agencies is not to lose in their race against technology, the challenge for policymakers is to
make our best judgments about the limitations of the existing statistics, as we design policies to
promote the economic well-being of our nations