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Vol. 31, No. 2

ECONOMIC REVIEW
1995 Quarter 2

An Introduction
to Currency Boards

2

by Owen F. Humpage and Jean M. Mclntire

The Seasonality
of Consumer Prices
;

by Michael F. Bryan and Stephen G. Cecchetti




FEDERAL RESERVE BANK
OF CLEVELAND

12

1

ECONOMIC

REVIEW

1995 Quarter 2
Vol. 31, No. 2

An Introduction
to Currency Boards

2

by Owen F. Humpage and Jean M. Mclntire
The usefulness of money lies in its ability to reduce transaction costs,
but this in turn depends on the public's confidence in the stability of
money’s purchasing power. Governments that lack an established rep­
utation for price stability must adopt strong institutional constraints
on their ability to inflate if they hope to achieve monetary credibility.
Recent events in Mexico, and the movement toward market-based
development strategies in Eastern Europe, Latin America, and Asia,
have kindled an interest in the pros and cons of currency boards as an
institution for providing monetary credibility in developing countries
— the subject of this article.

The Seasonality
of Consumer Prices

12

by Michael F. Bryan and Stephen G. Cecchetti
In reevaluating the evidence of seasonality in prices, the authors find
that seasonal price movements have become more prominent in the
relatively stable inflation environment that has prevailed since 1982.
They conclude that the amount of seasonality differs greatly by item,
making it difficult to generalize about seasonal price movements.
That is, seasonality is predominantly idiosyncratic in nature, a result
that contrasts with studies demonstrating a common seasonal cycle
in real economic variables. Given the statistical criteria used by the
Bureau of Labor Statistics to selectively seasonally adjust component
data, the likelihood of noise appearing in the aggregate Consumer
Price Index at a seasonal frequency is increased. For economists
interested in a high-frequency inflation statistic, this argues in favor
of seasonally adjusting the index after aggregation.




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An Introduction
to Currency Boards
by Owen F. Humpage and Jean M. Mclntire

Introduction
The usefulness of money lies in its ability to re­
duce transaction costs. This depends, in turn,
on public confidence in the stability of money’s
purchasing power. In acquiring the requisite
monetary credibility, governments face a trade­
off between 1) creating institutions that limit
their ability to generate inflation, and 2) relying
on an established record for actually achieving
and maintaining stable prices. Those govern­
ments lacking an established reputation for
price stability must adopt stronger institutions
to foster confidence in the purchasing power of
their money.
The recent peso crisis is a good example of
this trade-off. Mexico granted its central bank
greater autonomy and made commendable im­
provements in its monetary policy prior to
1994. Money growth and inflation slowed dra­
matically after 1992. Nevertheless, these gains
were not typical of Mexico’s broader experi­
ence and were too recent to constitute a credi­
ble monetary policy reputation. Following po­
litical turmoil in 1994, capital flows into Mexico
began to recede, and the country lost official
reserves. A marked rate differential between
 Mexico’s peso-denominated and dollar-indexed


Owen F. Humpage is an economic
advisor and Jean M. Mclntire is a
senior research assistant at the
Federal Reserve Bank ot Cleve­
land. The authors thank Allan
Meltzer, Anna Schwartz, Allan Wal­
ters, and Carlos Zarazaga for com­
ments during various stages of
this research.

debts prior to last December's devaluation in­
dicated that investors were becoming increas­
ingly worried about holding pesos. They feared
that Mexico would once again resort to infla­
tionary finance and devaluation. Without a
well-established track record for price stability,
the Bank of Mexico’s newfound autonomy
could not endow it with credibility.
Events in Mexico, coupled with more marketbased development strategies in Eastern Europe,
Latin America, and Asia, have kindled an inter­
est in currency boards as an institution for pro­
viding monetary credibility in developing coun­
tries (see Hanke and Schuler [1994] and Hanke,
Jonung, and Schuler [19931). A currency board
offers to exchange domestic currency for for­
eign exchange at a fixed rate, on demand, and
under all circumstances. It insures this offer by
fully backing the domestic monetary base with
a foreign-reserve currency and by setting the ex­
change rate as a matter of public law.
This currency-board primer begins by de­
scribing those salient features of the arrange­
ment that secure its monetary credibility .1 As

■ 1 Fieleke (1992) and Walters and Hanke (1993) also cover the
basics of currency boards.

3

we discuss in section I, full convertibility at a
fixed exchange rate ties money growth and in­
flation in a developing country to those meas­
ures in the reserve-currency country, indepen­
dent of whether a central bank or a currency
board manages the exchange-rate peg. In strik­
ing contrast to a central bank, however, an or­
thodox currency board never acquires domestic
assets, and this prevents it from financing fiscal
policies, sterilizing reserve flows, or otherwise
engaging in discretionary monetary policies.
In the second section, we consider three
important criticisms of currency boards. The first
suggests that fully backing a currency with
foreign-exchange reserves is needlessly costly,
especially when domestic assets might offer a
higher return. The second criticism questions
the appropriateness of fixed exchange rates,
because movements in nominal exchange rates
can promote needed changes in a country’s
terms of trade. The third criticism faults currency
boards for not acting as the lender of last resort,
a function that may be especially important to
developing countries. All things considered, cur­
rency boards' major advantage over central
banks is that for developing countries willing to
accept a diminution of monetary sovereignty
and some lessening in the responsiveness of
their terms of trade, a currency board provides a
stronger arrangement for acquiring a credible
commitment to price stability.

I. Securing Price Stability
Currency Boards
and the Monetary
Adjustment Mechanism
In large part, currency boards boost monetary
credibility because they link money growth in
a currency-board country to that in a reservecurrency country. Reserve currencies, like the
U .S . dollar and the German mark, function as
money beyond their national borders. The
countries that issue them have relatively welldeveloped financial sectors as well as reputa­
tions for comparatively low inflation rates.
Because they are widely accepted, reserve cur­
rencies provide good collateral against the
currency board’s promise of full convertibility.
Today, currency boards in Argentina, Hong
Kong, and Latvia utilize the U .S . dollar as their
reserve currency, while Estonia relies on the
German mark. Although we assume that
currency boards hold only a single reserve cur­
rency, they have often held multiple currencies
as well as reserves of gold and silver. Estonia,


for example, initially considered linking to the
European Currency Unit — a composite cur­
rency — and started its operations with gold
reserves (see Bennett [19931).
Because a currency board issues only do­
mestic notes against foreign exchange at a
fixed exchange rate, the money stock in a
currency-board country is related to the nation’s overall balance-of-payments position.
To illustrate this relationship, we assume that
commercial banks in the currency-board coun­
try operate on a fractional-reserve basis, hold­
ing currency-board notes (NB) in reserve
against domestic deposits.3 In the absence of
legal reserve requirements, as is often the case
under currency boards, banks determine the
amount and composition of their reserves
based on four factors: 1) the size and turnover
of deposits, 2) clearing obligations, 3) the pub­
lic’s relative demand for notes, and 4) the op­
portunity cost of holding reserves. The public
holds currency-board notes (Np) and com­
mercial bank deposits for transaction purposes.
Currency boards have often appeared in
countries that experience widespread currency
substitution. We assume, however, that only
currency-board notes and bank deposits serve
as money in the currency-board country. This
simplifies the analysis without altering any fun­
damental conclusions. By improving confi­
dence in the domestic monetary unit, a cur­
rency board might greatly reduce currency
substitution. On the other hand, allowing indi­
viduals to hold foreign currency and foreign
currency deposits, as in Argentina, might fur­
ther constrain a currency board’s ability to
renege on the arrangement and might heighten
its monetary credibility.
Under these circumstances, the monetary
base consists of currency-board notes held by
both commercial banks and individuals. The
money supply (AO, which consists of currencyboard notes held by the public and commer­
cial bank deposits, is a multiple of the mone­
tary base:

■ 2 Currency boards may also provide coin, a subject we ignore in
this article.
■ 3 Some currency boards have offered reserve deposit accounts to
commercial banks.

□
B 0 X 1
Balance Sheets for a Currency
Board and a Central Bank
Currency Board
Liabilities

Assets

Notes (Np + Nb)

Central Bank
Liabilities

Assets

Foreign exchange (R0)
Domestic assets (D)
Securities
Loans

Reserves and clearing
accounts
Currency held by the public
Net worth

NOTE: We assume a fixed exchange rate equal to one.
SOURCE: Authors.

where r is the average reserves-to-deposit ratio,
and c is the average ratio of notes to deposits
held by individuals.4
As the currency board’s balance sheet illus­
trates (see box 1), notes issued to the public
and to the banking sector cannot exceed the
currency board’s receipts of foreign-exchange
reserves (R0).5 The currency board’s holdings
of foreign-exchange reserves are, in turn, di­
rectly related to the balance of payments (see
appendix). According to the balance-ofpayments identity,

(2)

C +A K = AR o>

where C is the current-account surplus, AK
represents net private capital inflows, and
AR0 > 0 refers to an official acquisition of for­
eign exchange.
When the home country runs an overall
balance-of-payments surplus (C + A K > 0), the
currency board acquires foreign exchange.
Other things equal, the monetary base and
money stock expand. Similarly, when the home
country runs an overall balance-of-payments
deficit (C + AK < 0), its monetary base and
money supply shrink, other things equal. Con­
trary to common perception, a currency-board
country need not maintain a current-account
surplus to expand its monetary base. Develop­
ing countries, which rely on foreign capital for
growth, may experience current-account deficits




(3)

Mt =

c
C/Vg+ N p)j
r+ c

1+ c
(R o ^t
r+ c
'1 + c
c

i—
"t
+

Net worth

+
r—
H

Foreign currency reserves (R0)
Liquid reserve account
Investment reserve account
Surplus reserve account

and larger net-capital-account inflows, resulting
in an overall balance-of-payments surplus.
In summary, we can state the money stock in
a currency-board country at any time, T, as a
m ultiple of the monetary base, which in turn re­
flects the foreign-exchange holdings of the cur­
rency board (equal to the cumulation of all past
balance-of-payments surpluses and deficits):

f

(C ,+ AK,).

Equation (3) is an identity. Changes in the
money stock result from developments that si­
multaneously affect the overall balance of pay­
ments or the money multiplier. If, for example,
investors in the currency-board country decide
to shift wealth out of deposits in that country
and into deposits in the reserve-currency coun­
try, they would first exchange domestic deposits
for currency-board notes through their commer­
cial banks, and then exchange currency-board
notes for the reserve currency with the currency
b o a rd T h e domestic money supply would fall
and the overall balance of payments would shift
into deficit as investors deposited funds abroad.
Interest rates in the currency-board country
might rise, partially counteracting the desire to
invest in the reserve-currency country and
reducing the demand for currency-board notes
in line with the now-smaller supply. Prices
might also fall, encouraging exports.
All of these adjustments follow automatically
without government intervention. Unfortunate­
ly, they may take time, especially if wages and
prices are inflexible, and they may result in
some temporary dislocations in the currencyboard country (as, for example, resources shift
from the production of investment-related
goods to the provision of export goods).
Equation (3) indicates that the money stock
in the currency-board country will increase as

|
4 See Brunner (1973) for a general discussion of money multipli­
ers in an open economy. See also Osband and Villanueva (1993).
|
5 We assume throughout this paper that the exchange rate is fixed
and equal to one.
|
6 Most currency boards have dealt only with commercial banks,
which supply foreign exchange to their customers at competitive rates.

long as that country runs a balance-of-payments
surplus. For the currency-board country to
acquire reserves, the reserve-currency country
must supply more money than its own public
wishes to hold. As the reserve-currency country
increases its money supply, short-term interest
rates might fall and domestic prices might rise,
creating arbitrage opportunities relative to the
developing country and a balance-of-payments
deficit in the reserve-currency country. As per­
sons in the currency-board country exchange
newly acquired foreign exchange for currencyboard notes, the money stock in the currencyboard country increases.7
In the long run, this process should ensure
that money growth in the currency-board coun­
try approximates that in the reserve-currency
country.8 The currency-board country acquires
credibility at the expense of losing monetary
sovereignty to the reserve-currency country.
The key aspect of the adjustment process
outlined above is that it is automatic; no discre­
tionary policy changes took place. Under fixed
exchange rates, a central bank would face simi­
lar automatic adjustments, but unlike a currency
board, a central bank can offset — or sterilize
— the contractionary monetary effects of the
capital outflow. In contrast to a currency board,
the money stock for a central bank is deter­
mined according to
(4)

M=

1+ c
(Rn + D )
r+ c

where D is domestic assets, typically govern­
ment securities and loans to depository institu­
tions (see box 1). When a change in its foreignexchange reserves occurs, a central bank can
sterilize the effects on its domestic money sup­
ply through offsetting operations with its
domestic assets:
(5)

(ARn) = AD.

The size of the central bank’s portfolio of
foreign-exchange reserves limits its ability to
sustain a reserve loss associated with a balanceof-payments deficit. This highlights a key insight
of the monetary approach to the balance of
payments: Central banks maintain balance-ofpayments deficits (surpluses) by supplying more
(less) money than their citizens desire.
If a central bank accurately identifies as
temporary the underlying problem causing a
balance-of-payments deficit or surplus, steriliza­
tion might be beneficial for avoiding interim
economic adjustments and dislocations. If, how­
ever, the underlying problem is long term or is


related to uncertainty about government or cen­
tral bank policies, sterilization can actually
worsen the capital outflow. Speculators realize
that the probability of a devaluation increases as
a central bank’s reserves dwindle. They are
likely to move funds out of the country, thereby
aggravating the situation. Consequently, while
central banks may avoid adjustment to tempo­
rary balance-of-payments disequilibria, they
have no advantage over currency boards when
the underlying problem is persistent.

No Domestic
Assets
Unlike a central bank, an orthodox currency
board never acquires domestic assets. Among
other things, this precludes the currency board
from buying home-government debt obliga­
tions, from lending to state-run industries, or
from making loans to local banks. This crucial
prohibition separates the currency board from
the government’s fiscal activities and prevents it
from engaging in discretionary monetary policy.
As Ow (1986) and Schuler (1992) both point
out, the decision to abandon currency boards
in the 1950s did not stem from their failure to
provide stable money. Instead, these newly
independent developing countries believed that
an inability to conduct discretionary monetary
policy would hamper their development efforts
(see Schwartz [1993D- Consequently, they es­
tablished central banks.9 In actuality, most de­
veloping countries have, relied on their central
banks to undertake a myriad of fiscal opera­
tions, including monetizing government activi­
ties (see Fry [19931 and Calvo and Vegh [1992]).
In addition to preventing currency boards
from acquiring govemment-debt instruments,
the prohibition against holding domestic assets
appears to constrain deficit spending. Absent
inflationary finance, governments seem more
concerned about fiscal competition with private
borrowers for available credit (see Osband and
Villanueva [19931). Ow (1986, pp. 47-48) shows
that under currency boards, Singapore and
■ 7 On the connection between monetary disequilibria and the bal­
ance of payments, see Frenkel and Mussa (1985). Price increases following
a one-time rise in the reserve-currency country’s money supply will eventu­
ally restore monetary equilibrium and eliminate the balance-of-payments
deficit.
■ 8 The measured inflation rate may diverge because of nontradablegoods prices, but should remain cointegrated. See discussions about
Hong Kong in Schwartz (1993) and Ow (1986).

■ 9 Ironically, the success of currency boards in stabilizing the cur­
rency often facilitated the move to a central bank.

6

Hong Kong typically operated with government
budget surpluses, while other former British
colonies that abandoned their currency boards
persistently maintained large deficits.
The prohibition on holding domestic assets
prevents the currency board from engaging in
monetary policy, but as Ow (1986, pp. 71-75)
argues, the government retains a limited ability
to influence the domestic money stock. Gov­
ernments in currency-board countries typically
hold portfolios of assets denominated in the
foreign-reserve currency. These portfolios are
independent of the currency board and, as we
discuss below, often result from currency-board
profits. By converting the foreign exchange
acquired from the sale of these assets into
currency-board notes, the government can alter
the domestic money supply. Hence, the gov­
ernment might finance a fiscal expenditure or
respond to an exogenous increase in money de­
mand (see section II, “Lender of Last Resort”) 10
A government’s ability to undertake such a pol­
icy depends on its holdings of foreign-currency
assets (or on its ability to borrow abroad). Un­
like discretionary central-bank actions, however,
this policy cannot undermine the currency’s re­
serve backing or the currency board’s credibility.

II. Criticism of
Currency Boards
100 Percent
Reserve Backing
in Foreign Exchange
As Schuler’s (1992) historical survey indicates,
currency boards typically apportioned their
foreign exchange among three accounts. They
held approximately 30 to 50 percent of the as­
sets backing their notes in a liqu id reserve,
consisting of high-quality, marketable securities
of the reserve-currency country that mature in
less than one year. They maintained 50 to 70
percent of the assets backing their notes in an
investment reserve that comprised higheryielding securities with a longer maturity and
somewhat greater risk. This split between liq­
uid and investment reserves was possible
because the public used a relatively fixed pro­
portion of notes and coin in circulation to fi­
nance day-to-day transactions and, under nor­
mal circumstances, would not redeem this
amount for reserve assets. The investment
reserve was an important source of profit for
the currency board.
Besides the 100 percent reserve backing

http://fraser.stlouisfed.org/apportioned to the liquid and investment
Federal Reserve Bank of St. Louis

reserves, Schuler found that currency boards
usually held an additional amount of foreign
exchange, equal to approximately 5 to 10 per­
cent of their note issuance, in a surplus reserve.
This surplus ensured that possible capital losses
on the investment reserves would never pull
the total amount of foreign-exchange backing
below the 100 percent necessary to fully guar­
antee all notes in circulation.11 The surplus re­
serve grew from profits generated on currencyboard investments.
Schuler (1992, p. 188) found that the costs of
operating currency boards were typically very
small and that only two were unprofitable.
Even currency boards that started operations
holding less than 100 percent in reserve back­
ing were able to build their foreign-exchange
portfolios to the required level through earn­
ings on their investments. Typically, any profits
in excess of approximately 110 percent of the
currency board’s notes in circulation were re­
mitted to the local government, enabling the
government to acquire the aforementioned
portfolio of reserve-currency assets.
By issuing its own currency in exchange
for the reserve currency and by investing its
reserves in earning assets, governments in
currency-board countries garnered seigniorage
(profits associated with the issuance of base
money) that they otherwise would have lost
because of currency substitution. Unlike central
banks, which earn seigniorage primarily from
inflation, currency boards gain seigniorage only
as interest from assets denominated in the re­
serve currency. Historically, capturing seignior­
age has been an important reason for establish­
ing currency boards.
Critics of currency boards have argued that
backing 100 percent of the monetary' base with
foreign-reserve assets when domestic assets
yield more is needlessly costly. In their view,
the currency board could place its ini'estment
resen t in higher-yielding domestic assets with­
out unduly weakening itself. Argentina cur­
rently allows up to one-third of its reserv es to
be held in domestic instruments (see Bennett
■ 10 Following the monetary approach to the balance of payments,
an exogenous increase in the money supply, other things equal, will even­
tually dissipate through a balance-of-payments deficit. Hence, the discre­
tionary actions of the government must simultaneously increase the
demand for money. See Frenkel and Mussa (1985)

■

11 Osband and Villanueva (1993, pp 206—07) argue that with
reserves large enough to cover a likely valuation change, a currency board
could exist with a flexible exchange rate. Although Singapore is a prime
example (see Ow [1986, pp. 87-881), a floating exchange rate greatly
reduces the credibility of the system. Thus, many analysts no longer con­
sider Singapore to have a currency board (see Schwartz [1993]).

[1994, p. 6]). Some colonial currency boards
did invest reserves in domestic assets and
thereby evolved into central banks capable of
discretionary policies.12
The opportunity cost of holding foreign
reserves, however, actually reflects country risk
and exchange-rate risk and is not a cost of
operating a currency board. If capital markets
are efficient, if capital is perfectly mobile, and if
domestic and foreign assets are perfect substi­
tutes, arbitrage will equate real returns across
countries. The higher interest rates that inves­
tors require of developing countries offset the
risks of currency devaluation, confiscatory
taxes, and capital restrictions. A currency board,
by providing a stable currency at a fixed
exchange rate and by constraining fiscal policy,
may reduce these risks, thereby encouraging
domestic investment and equating returns. For
a currency board to hold higher-yielding, but
riskier, domestic assets may impinge on its abil­
ity to instill confidence. As individuals substi­
tute foreign for domestic currencies, they incur
higher transaction costs, and the currencyboard government loses seigniorage.

Fixed Exchange
Rates
Confidence in a currency-board system results
because it guarantees complete convertibility at
an absolutely fixed exchange rate.13 In addition
to promoting monetary credibility7, fixed ex­
change rates reduce the transaction costs asso­
ciated with exchange-rate volatility that is unre­
lated to fundamentals. These transaction costs
could be substantial for small economies that
are heavily dependent on international trade
and investment. On the other hand, currencyboard systems prevent exchange-rate changes
from helping an economy adjust to economic
shocks. Consequently, any cost-benefit analysis
of currency boards must consider the possible
trade-off between monetary' policy credibility
and smoother economic adjustments.14
When domestic wages and prices are inflex­
ible or when international arbitrage is other­
wise slow, flexible exchange rates can hasten a
country’s adjustment to idiosyncratic economic
disturbances by facilitating rapid changes in
the terms of trade. ^ As one might expect, if
the currency-board country and the reservecurrency country experience similar economic
shocks, the bilateral terms-of-trade changes will
not aid adjustment. Fixed exchange rates would
then
 seem optimal. Countries with comparable


economic makeups are likely to experience
similar and coincidental economic shocks.
When shocks are dissimilar, fixed exchange
rates can be feasible if other variables facilitate
adjustment. If, for example, the currency-board
country has a sufficiently well-diversified econ­
omy (in the sense that shocks are negatively
correlated across its producing sectors), changes
in the international terms of trade may not be
necessary in the adjustment process, since
unemployed resources in one sector will mi­
grate to other sectors. Similarly, adjustment in
the terms of trade will prove unnecessary if fac­
tors of production are highly mobile across
international borders. Then, arbitrage quickly
eliminates even small differences in prices or
interest rates. Closely integrated financial mar­
kets or fiscal transfers across countries could
also ease transitions to temporary shocks with­
out recourse to exchange-rate changes. Finally,
when prices and wages are highly flexible, the
terms of trade can adjust quickly without a
change in the nominal exchange rate. The
appropriateness of a fixed exchange rate in­
volves a country-by-country analysis.
In addition, Schwartz (1993, pp. 179-82)
argues that the choice of an exchange-rate peg
is complicated because the reserve-currency
country might not be one of the currency-board
country's closest trading partners. A change in
the reserve-currency country’s exchange rate
might alter the currency-board country’s com­
petitive position relative to its major trading
partners. A currency board pegged to the Ger­
man mark, for example, would have experi­
enced an 11 percent appreciation relative to the
dollar (and to countries pegged to the dollar) in
1994. Schwartz argues that this was not as
much of a problem for currency boards operat­
ing under the gold standard as it might be
today under more generalized floating.

■ 12 The Southern Rhodesia Currency Board and the East African
Currency Board evolved in this manner (see Schuler [1992, pp. 106-08]).
See also Schwartz (1993) and Hanke and Schuler (1991).
■ 13 Strictly speaking, the currency board does not peg the
exchange rate, but fixes the rate at which currency-board notes trade for the
currency of the reserve country. An exchange rate at which bank deposits
trade for foreign exchange will deviate within small arbitration points from
the currency board’s rate (see Bennett [1993, pp. 18-20]).

■ 14 Ishiyama (1975) provides a survey of the optimal-currencyarea literature, engaging in a cost-benefit analysis of fixed and flexible
exchange rates and discussing the examples that follow in more detail.
■ 15 The terms of trade are the price of a country’s exports relative to
the price of its imports, expressed in a common currency.

Lender of
Last Resort
Currency boards enhance monetary credibility
by eliminating the opportunities for discre­
tionary monetary policies and by guaranteeing
the convertibility of domestic currency at a
fixed exchange rate. They do not, however,
guarantee the convertibility of bank deposits,
even though banking sectors in small, open,
developing countries may be particularly sus­
ceptible to macroeconomic shocks. The chief
criticism of currency boards, therefore, has
been that, unlike central banks, they do not
serve as a lender of last resort (LLR).
In periods of economic or financial crises,
uncertainty about banks’ solvency often causes
individuals to shift their monetary wealth from
bank liabilities to currency. With runs impend­
ing, banks also attempt to shore up their credi­
bility by holding more reserves. As the public
increases its cash-to-deposit ratio and as banks
increase their reserve-to-deposit ratio, the
money supply contracts, leading to a general
deflation (see equation [3D. A traditional LLR
can avoid a contraction in the money supply
and prevent a collapse of temporarily illiquid,
but solvent, commercial banks by accommodat­
ing the increased demand for high-powered
money.16 Usually, the LLR fulfills this function
through discount-window operations, but a
central bank can also undertake open-market
operations. Since an orthodox currency board
neither holds reserves against commercial bank
deposits nor undertakes discretionary monetary
policy, it is unable to perform LLR operations.
Recent problems with bank liquidity in Argen­
tina illustrate the vulnerability of currency
boards to banking crises.
Proponents of currency boards note that
banks in currency-board countries have often
been branches of large, global banks headquar­
tered in the reserve-currency country. They
believe that currency-board arrangements —
domestic notes backed with foreign-exchange
reserves at a fixed exchange rate — eliminate
exchange risk and thereby encourage branch
banking. Borrowing from a foreign parent then
affords the domestic branch bank an elastic
supply of reserve currency.17 Selgin (1989)
argues that the ability of commercial banks to
branch reduces the likelihood of banking
crises, since branching effectively enables com­
mercial banks to diversify. A currency-board
country, despite an undiversified economic
base, could effectively diversify its financial sys­
tem
through an unregulated (or minimally reg­

http://fraser.stlouisfed.org/ulated) branch banking network.
Federal Reserve Bank of St. Louis

Schwartz (1993) disputes the contention that
currency boards encourage branch banking.
She suggests that the extensive branch banking
found in British colonial currency-board coun­
tries stemmed from their colonial status, not
from their having currency boards. Many devel­
oping countries that today might benefit from a
currency board, such as Mexico, have not here­
tofore encouraged the entry of foreign banks
and do not have extensive branch banking net­
works. Whether sufficient branch banking
would follow the establishment of a currency
board remains uncertain.18
Many currency-board countries appoint a
wholly separate monetary authority to regulate
commercial banks (by setting capital require­
ments and reserve requirements) and to provide
LLR functions through a discount-window facil­
ity. The Bank of Estonia, for example, estab­
lished an Issuing Department, which is a cur­
rency board, and a Banking Department, which
regulates banks and acts as the LLR (see Bennett
[1993D-19 Under such an arrangement, the inde­
pendent monetary authority would need to hold
either currency-board notes or foreign-reserve
currency. As long as the LLR finances its opera­
tions out of the currency board’s surplus
reserves (as in Estonia) and avoids holding ob­
ligations of the fiscal authorities, it will not nec­
essarily undermine the credibility of currencyboard notes. The monetary authority might also
lower reserve requirements during banking
crises, thereby encouraging liquid banks to lend
temporarily to illiquid institutions.20
As noted above, governments in currencyboard countries often acquire foreign assets, be­
cause the currency boards remit excess reserves
to them. The fiscal authority of a currency-board
country can also inject liquidity into the banking

■ 16 Humphrey (1993) views bank runs as primarily disrupting the
payments system, while Goodhart (1987) views them as primarily affecting
banks' ability to intermediate between borrowers and lenders.
■

17

This argument applies to bank borrowing in general.

■ 18 Ow (1986) argues that a developed branch banking network
retards the development of other financial institutions.
■ 19 Schuler (1992) suggests that the original model for currency
boards was the Bank of England, which under the Bank Charter Act of 1844
split into separate Banking and Issuing Departments. Schwartz (1993) dis­
putes this, arguing that British authorities often attempted to suppress the
development of currency boards.
■ 20 Argentina's currency board, which sets reserve requirements,
has lowered these requirements selectively in response to the current
banking crisis. Argentine banking authorities have actively encouraged
insolvent banks to merge with healthy institutions

9

T A B L E

A- 1

A Balance-of-Payments Example
Credits

Current Account
Trade in goods
and services
Interest/dividends
Unilateral transfers
Capital Account
Direct investments
$ 10,000
Portfolio investments
Change in bank
liabilities
$15,000
Change in bank assets
Official Reserves
Change in foreignexchange reserves
Change in other
reserve assets

$

Debits

Net

-$15,000

-$15,000

$ 10,000

Appendix
-$15,000

5,000

Balance-ofPayments
Accounting
$ 5,000

NOTE: We assume a fixed exchange rate equal to one.
SOURCE: Authors.

system by selling foreign assets or by borrowing
abroad. The Monetary Authority of Singapore
has done this (see Ow [1986]), and Argentina
has recently borrowed from the International
Monetary Fund and from private sources to help
ease the restructuring of its banking system.
Although a Banking Department or the gov­
ernment might operate as a LLR, its portfolio of
foreign assets and its ability to borrow abroad
limit its capacity to create notes within the
currency-board framework and to fend off a
banking crisis. In contrast, a central bank that
issues fiat money does not face limitations on its
ability to create reserves during a banking crisis.
Consequently, one cost of operating a currencyboard system, particularly in relatively undiver­
sified developing economies, may be a greater
susceptibility to banking crises.

III. Conclusion
Because governments can generate revenue
from monetary expansions, no institutional
arrangement for stabilizing the value of money
is fully credible. A reputation for achieving and
maintaining a low inflation rate is necessary.
After a country has acquired a credible rep­

utation
for maintaining reasonably stable


prices, many different institutional arrange­
ments may be capable of sustaining it. In the
interim, however, a trade-off exists between
strong institutional constraints and an estab­
lished reputation. Developing countries with
histories of inflation and devaluation must
adopt much stronger institutional constraints
on their ability to inflate than developed coun­
tries have done if they are to achieve even
moderately comparable levels of credibility.
Currency boards offer an approach whose
costs and benefits deserve closer consideration.

A nation’s balance of payments is a comprehen­
sive accounting record of all transactions
between its residents and the rest of the world.
Although they are typically published only on a
net basis, balance-of-payments statistics incor­
porate double-entry-accounting techniques. Any
transaction that creates a receipt (such as an
export) is a credit, and any transaction that cre­
ates a payment (such as an import) is a debit.
Economists often group accounts into three
categories. The current account includes trade
in goods and services, receipts or payments of
interest and dividends, and unilateral transfer
payments to, or from, foreigners. The capital
account includes long-term capital flows, such
as direct investments and long-term portfolio
investments, and short-term capital flows, such
as investments in short-term money market in­
struments or acquisitions of bank deposits. It
also includes private and government capital
flows other than the government’s “official” cap­
ital flows. Official reserves include official trans­
actions in various reserve assets, such as foreign
exchange. Under floating exchange rates, gov­
ernments use these assets to influence their
exchange rates. Under fixed exchange rates,
governments use these transactions to offset net
overall debits or credits in the other accounts,
since exchange rates would otherwise move to
balance these accounts. Acquisition or losses of
official reserves affect the balance sheet of a
nation’s central bank or currency board, as we
described in the text.
Since every international transaction creates
both a debit and a credit in the balance of pay­
ments, the ledger always balances. If, for exam­
ple, a country imports a $15,000 foreign car and

10

pays for it with a check drawn against a domes­
tic bank, the balance of payments records the
imported car as a debit and lists the foreign
claim on a domestic bank as a credit (see table
A -l). Essentially, the country exports owner­
ship of a bank deposit in order to import the
car. If the foreigner decides to acquire some­
thing else with the bank account, like stocks,
bonds, land, or computers, additional offsetting
debits and credits will enter the account. With
fixed exchange rates, if the foreigner elects to
exchange the bank account back into his own
currency, a debit appears under bank-related
capital flows, and a corresponding credit
appears under official reserves, as the central
bank pays out foreign exchange from its official
holdings.
Table A -l assumes that the foreigner pur­
chases $10,000 of stock and repatriates $5,000
of his bank claim. Should the monetary author­
ity not make this exchange, the foreigner’s sales
of domestic currency will cause that currency to
depreciate. This in turn affects private decisions
about exports, imports, and capital transactions
in such ways as to restore balance to the cur­
rent and capital accounts.
Because of the double-entry nature of the
accounts, a surplus or deficit can exist only in a
subset of the accounts. How one defines a
balance-of-payments deficit or surplus largely
depends on which accounts one finds interest­
ing or useful to isolate. In our case, we define
the overall balance as consisting of items in the
current and capital accounts. Our example re­
cords a $5 billion overall balance-of-payments
deficit. (Note that the balance of payments re­
cords the loss of foreign-exchange reserves as a
credit. We import a foreign car, a debit, and pay
for it by exporting stock and foreign reserves,
both credits.)




References
Bennett, Adam G.G. “The Operation of the
Estonian Currency Board,” International
M onetary Fund S taff Papers, vol. 40, no. 2
(June 1993), pp. 451-71.
__________ .“Currency Boards: Issues and
Experiences,” International Monetary Fund,
Paper on Policy Analysis and Assessment,
PPAA/94/18, September 1994.
Brunner, Karl. “Money Supply Process and
Monetary Policy in an Open Economy,” in
Michael B. Connolly and Alexander K.
Swoboda, eds., In tern ation al Trade an d
Money: The Geneva Essays. Toronto: Univer­
sity of Toronto Press, 1973, pp. 127-66.
Calvo, Guillermo A., and Carlos A. Vegh. “Cur­
rency Substitution in Developing Countries:
An Introduction,” International Monetary
Fund, Working Paper WP/92/40, May 1992.
Fieleke, Norman S. “The Quest for Sound
Money: Currency Boards to the Rescue?”
Federal Reserve Bank of Boston, New
England Econom ic Review, November/
December 1992, pp. 14-24.
Frenkel, Jacob A., and Michael L. Mussa. “Asset
Markets, Exchange Rates, and the Balance of
Payments,” in Ronald W. Jones and Peter B.
Kenen, eds., H an dbook o f In tern ation al Eco­
nomics, vol. 2. New York: North-Holland,
1985, pp. 679-740.
Fry, Maxwell. “The Fiscal Abuse of Central
Banks,” International Monetary’ Fund, Work­
ing Paper WP/93/58, July 1993Goodhart, C.A.E. “Why Do Banks Need a Cen­
tral Bank?” O xford Econom ic Papers, vol. 39,
no. 1 (March 1987), pp. 75-89.
Hanke, Steve H., Lars Jonung, and Kurt Schuler.
Russian Currency a n d Finance: A Currency
B oard A pproach to Reform . New York: Routledge, 1993.
Hanke, Steve H., and Kurt Schuler. “Ruble
Reform: A Lesson from Keynes,” Cato Jo u r­
nal, vol. 10, no. 3 (Winter 1991), pp.
655-66.

11

________ , and_______ . Currency B oards fo r
Developing Countries: A H andbook. San
Francisco: International Center for Economic
Growth, 1994.
Humphrey, Thomas. “Lender of Last Resort,” in
Peter Newman, Murray Milgate, and John
Eatwell, eds., The New Palgrave D ictionary
o f Money>an d Finance. London: MacMillan
Press, 1993, pp. 571-74.
Ishiyama, Yoshihide. “The Theory of Optimum
Currency Areas: A Survey,” International
M onetary Fund S taff Papers, vol. 22, no. 2
(July 1975), pp. 344-83.
Osband, Kent, and Delano Villanueva. “Indepen­
dent Currency Authorities," International
M onetary Fund S taff Papers, vol. 40, no. 1
(March 1993), pp. 202-16.
Ow, Chwee-Huay. “The Currency Board Mone­
tary System — The Case of Singapore and
Hong Kong,” Johns Hopkins University,
Ph.D. dissertation, 1986.
Schuler, Kurt A. “Currency Boards," George
Mason University, Ph.D. dissertation, Spring
1992.
Schwartz, Anna J. “Currency Boards: Their
Past, Present, and Possible Future Role,”
C arnegie-Rochester C onference Series on
Public Policy, vol. 39 (December 1993), pp.
147-87.
Selgin, George A. “Legal Restrictions, Financial
Weakening, and the Lender of Last Resort,”
Cato Jou rn al, vol. 9, no. 2 (Fall 1989), pp.
429-59.
Walters, Alan, and Steve H. Hanke. “Currency
Boards,” in Peter Newman. Murray Milgate,
and John Eatwell, eds., The New Palgrave
D ictionary o f Money' an d Finance. London:
MacMillan Press, 1993, PP- 558-61.




The Seasonality of
Consumer Prices
by Michael F. Bryan and Stephen G. Cecchetti

Introduction
Early in 1993, the Consumer Price Index (CPI)
reversed course and increased at an annualized
rate of roughly 4V3 percent—about V/2 percent­
age points above its average growth rate during
the previous six-month period. The prospect of
rising inflation sent shock waves through capi­
tal markets and attracted the attention of mone­
tary policymakers. The minutes of the Federal
Open Market Committee (FOMC) meeting of
May 18, 1993 document a commitment to shift
the stance of monetary policy if the inflation
statistics continued their ascent:
In the view o f a majority o f the m em b ers,
w a g e an d p rice d ev elo p m en ts o v e r recen t
m on th s w ere sufficiently w orriso m e to w arrant
p osition in g policy' for a m o v e tow ard restraint
sh ould signs o f intensifying inflation co n tin u e
to multiply.

But in the months immediately following the
FOMC’s “asymmetric directive,” the growth rate
of the CPI moderated sharply, averaging less
than 2 V2 percent per annum in the final six
months of 1993. For the year as a whole, the
CPI
rose only about 234 percent, approximately

http://fraser.stlouisfed.org/ *4 percentage point below 1992’s rate.
Federal Reserve Bank of St. Louis

Michael F. Bryan is an economist
and consultant at the Federal Re­
serve Bank of Cleveland, and
Stephen G. Cecchetti is a profes­
sor of economics at The Ohio
State University and an associate
of the National Bureau of Eco­
nomic Research. The authors
gratefully acknowledge the com­
ments of Steven Braun, James
Buszuwski, Claire Gallagher,
Jagadeesh Gokhale, Joseph
Haubrich, Jeffrey Miron, and
Peter Rupert on an earlier version
of this article.

A popular interpretation of these events is
that the inflationary' scare of 1993 was a result
of “seasonal” price increases that were not part
of a more persistent inflationary process. In
fact, several studies have identified a pattern of
large price increases during the first sev eral
months of every' year followed by a more mod­
erate inflation performance over the balance of
the year.1 Indeed, prior to this recent experi­
ence, economists generally presumed that, rela­
tive to the real economy, prices contained little
seasonal variation.
These observations raise an important ques­
tion. Has the seasonality' in prices changed sub­
stantially over the past quarter century? Perhaps
seasonal variability was obscured by a domi­
nant cyclical variability in prices over much of
the post-World War II period. We do, in fact,
find that seasonal price movements have
become more prominent in the relatively stable
inflation environment that has prev ailed since
1982. Furthermore, we find that a substantial
share of price seasonality is idiosyncratic in
nature, which implies that seasonal patterns in

■

1 See, for example. Biehl and Juckj (1993)

13

FI GURE

1

CPI, All Items
(not seasonally adjusted)
Percent change

1967

1972

1977

1982

1987

1992

SOURCE: U.S. Department of Labor, Bureau of Labor Statistics.

FI GURE

2

Women’s Apparel Prices
(not seasonally adjusted)
Percent change

10

1967

1972

1977

SOURCE: U.S. Department of Labor, Bureau of Labor Statistics.

individual price series are partially negated in
the process of aggregation.
Figure 1 shows monthly movements for the
CPI without seasonal adjustment. Though
monthly consumer prices are certainly volatile,
there is little obvious seasonal movement in the
aggregate data. However, prices of most com­
ponents display a distinct seasonal pattern, and
for some, such as women’s apparel (figure 2),
the seasonal pattern is a prominent feature of
the data.
In this paper, we reevaluate the evidence of
seasonality in consumer prices in light of the
relatively stable inflation seen in the United
States during the past 10 years. In section I, we
 describe and catalog deterministic seasonality


in individual consumer prices. Section II con­
siders seasonality in aggregate prices and the
procedure used by the U.S. Labor Department’s
Bureau of Labor Statistics (BLS) for adjusting
individual price data to eliminate seasonal vari­
ation. We show that this procedure allows idio­
syncratic noise to become incorporated into the
price data. We consider the use of a limitedinfluence estimator, the median CPI, as a
method of reducing seasonal noise.2 We then
briefly describe the case of stochastic seasonal­
ity in consumer prices before concluding in
section III.

■ 2

See also Bryan and Cecchetti (1994).

TABLE

1

Deterministic Seasonality
in the CPI, 1967-1993
(using Newey-West correction)

Months

Jan.
Feb.
Mar.
April
May
June
July
Aug.
Sept.
Oct.
Nov.
Dec.

Jan. 1967Nov. 1993
t-stat
«S

0.054
0.002
0.102
0.029
0.018
0.067
-0.053
-0.006
0.121
0.024
-0.100
-0.165

1.50
0.09
0.27
0.88
0.56
2.53
-1.46
-0.19
3.00
0.80
-3.09
-4.00

R2

0.068
Wald 88.040
p-value 0.000

Jan. 1967Jan. 1982Dec. 1981_________Nov. 1993
t-stat
t-stat
«s

-0.009
0.011
0.019
0.014
0.014
0.077
-0.052
-0.058
0.074
0.039
-0.038
-0.091
0.032
44.650
0.000

-0.27
0.29
0.39
0.33
0.38
3.21
-0.89
-1.31
1.34
0.76
-1.09
-1.98

0.139
-0.007
0.000
0.050
0.024
0.055
-0.054
0.059
0.181
0.007
-0.176
-0.278

2.80
-0.25
0.01
0.92
0.47
1.12
-1.83
1.75
4.21
0.29
-4.53
-6.53

0.320
330.600
0.000

SOURCE: Authors’ calculations.

I. The Deterministic
Seasonality of Prices
Miron (1990) identifies broad classifications of
seasonal variation for a variable x t, the most
common being deterministic seasonality, speci­
fied as
s
(1)
xt =
a s d st + e t,
a
-= i
where d f is a dummy for season s (d st = 1 in
season 5 of period t, 0 otherwise), a s is the
mean of xt in season 5, 5 is the number of sea­
sons per year (four for quarterly data and 12
for monthly data), and e t is a stationary stochas­
tic process.3
Although data on real output and nominal
money exhibit substantial deterministic season­
al variation, it is curious to note the absence of
a deterministic seasonal pattern in aggregate
prices. For example, Barsky and Miron (1989)
find that seasonal dummies explain nearly 88
percent of the quarterly variation in U.S. real
GDP, more than 92 percent of real final sales,
and more than 50 percent of the nominal
money stock during the postwar period. Beau­
lieu and Miron (1990) obtain similar results at a




monthly frequency for retail sales, industrial
production, and money growth for a broad
cross-section of countries.
However, seasonal variation has accounted
for only a small share of the variation in aggre­
gate prices in the postwar period (for example,
less than 4 percent of the monthly variation in
the CPI). Perhaps exogenous seasonal increases
in aggregate supply fortuitously coincide with
increases in seasonal demand, resulting in the
substantial seasonality of real spending and
output while virtually eliminating the seasonal
behavior of prices. This explanation has been
dismissed as implausible by Barsky and Miron
(1989) and Mankiw and Miron (1990).4 Alter­
natively, it may be that aggregate supply is
perfectly elastic. By extension, then, interestrate targeting policies that do not adjust for
fluctuations in the real rate of interest at a sea­
sonal frequency may have real effects that are
manifested in exaggerated seasonal output and
employment fluctuations (Mankiw and Miron
[1990DBut the observed lack of seasonality in
prices has been influenced by the predominant
cyclical pattern of inflation during the 1970s
and early 1980s, a pattern that has since been
dramatically reduced. And as U.S. inflation has
settled into a more stable pattern, seasonal vari­
ation has become a relatively more important
and more obvious source of monthly price fluc­
tuations. That is, there is certainly less appear­
ance of price stickiness at a seasonal frequency
since 1982.
We use equation (1) to estimate the deter­
ministic seasonal pattern in the monthly CPI
over the 1967 to 1993 period and over two
subperiods: 1967 to 1981, and 1982 to 1993
(table 1). For the full period, we find that
deterministic seasonality accounts for about 7
percent of the monthly variation in the CPI—
similar to the results found by Beaulieu and
■ 3 Throughout the paper, we examine seasonality in the log differ­
ence of prices. In contrast, the BLS applies a two-sided ARIMA X-11 filter to
the level of prices that includes both past and future data. In limited instances
where a trend shift in the data is suspected, the BLS seasonally adjusts
using intervention analysis (see Buszuwski and Scott [1988]). We chose our
method for two reasons: First, since our major interest is inflation, our goal
is to seasonally adjust the growth rate of prices, not their levels. Second, we
wish to model seasonality as either a deterministic or a simple stochastic
process, in order to preserve the timing patterns in the data.
■ 4 This explanation may not be as implausible as it initially seems.
We find substantially more seasonality in energy prices after the collapse of
OPEC price controls. It may well have been that OPEC price targets, which
were managed by production quotas, operated at a seasonal frequency to
maintain a constant price of oil. This accentuated seasonal behavior in
energy prices may be an important seasonal cost fluctuation for a broad
range of commodities in the post-1981 period.

15

TABLE

2

Deterministic Seasonality
in 36 CPI Components, 1982-1993
(using Newey-West correction)8
Variances
Seasonal

CPI—all items
Food away from home
Auto repair
Apparel services
Personal services
Housekeeping services
Medical commodities
Entertainment commodities
Housekeeping supplies
Toilet goods
Cereals
Shelter
Entertainment services
Other transp. commodities
Medical services
Dairy
Other utilities
Household furnishings
Alcoholic beverages
Other food
Public transportation
Meats
Other transp. services
New vehicles
Used vehicles
Tobacco
Other apparel
Infants’ apparel
Books and supplies
Footwear
Educational services
Men’s apparel
Motor fuel
Fruits
Gas and electricity
Fuel oil
Women’s apparel

0.01406
0.00165
0.00616
0.00773
0.00952
0.01233
0.01643
0.02178
0.02290
0.02549
0.02692
0.02785
0.02902
0.03478
0.03849
0.03989
0.04266
0.04366
0.06237
0.12482
0.12575
0.12898
0.13856
0.16027
0.27306
0.32535
0.47608
0.68437
0.76361
0.83807
1.08842
1.30880
1.78895
1.79705
2.15611
2.71104
7.70884

a. Variances reported are scaled by 10,000.
SOURCE: Authors’ calculations.




Unconditional

0.04394
0.01868
0.04310
0.06910
0.06754
0.14055
0.06702
0.10541
0.13655
0.19028
0.09709
0.12018
0.09736
0.28866
0.06792
0.28452
0.26639
0.16937
0.30373
0.20477
1.12806
0.76826
0.27041
0.24708
0.87139
1.27310
1.79247
2.94988
1.01300
1.22939
1.37163
1.58662
10.13414
6.02819
278571
14.95497
9.40582

R2

0.32
0.09
0.14
0.11
0.14
0.09
0.25
0.21
0.17
0.13
0.28
0.23
0.30
0.12
0.57
0.14

0.16
0.26
0.21

0.61
0.11
0.17
0.51
0.65
0.31
0.26
0.27
0.23
0.75
0.68
0.79
0.82
0.18
0.30
0.77
0.18
0.82

Miron (1990). In the earlier, volatile inflation
subperiod, deterministic seasonality represents
about 3 percent of the monthly variation in
consumer prices. Since 1982, however, season­
ality accounts for approximately 32 percent of
the monthly price movement.
Estimated over the 1982 to 1993 subperiod,
the amount of deterministic seasonality in
prices, as measured by the seasonal variance,
^ (a * ), differs greatly by item, making it diffi5=1
cult to generalize about seasonal price move­
ments from the 36 consumer items considered
here (table 2). For example, the largest seasonal
variation in prices occurs in women's apparel
(last row), where seasonal fluctuations also rep­
resent 82 percent of the total price variation. At
the other extreme, food away from home (first
row) exhibits a very small amount of seasonal
variation. Furthermore, these variations account
for only about 9 percent of the total price varia­
tion in this category.
In some cases, seasonal variation is relatively
large, yet still amounts to a small share of the
total variation in the individual price series. For
example, fuel oil and motor fuel prices each
rank high in terms of deterministic seasonal
variation, but in both cases such seasonality
accounts for only 18 percent of their total price
variation. However, while the seasonal varia­
tion in medical services prices is rather small,
seasonality contributed to a relatively high pro­
portion of the category’s total price variation
(57 percent).
A casual reading of the seasonal patterns
fails to reveal an easily identifiable origin of the
seasonal variation of prices (table 3). Supply
fluctuations may explain much of the seasonal
behavior in food prices. Specifically, cereal and
fruit prices show repeating price declines in the
fall, when harvests are generally great, but large
positive seasonals in January, when harvests
are small. Public transportation prices show a
single, large positive seasonal variation in Janu­
ary, and natural gas and electricity prices are
generally adjusted upward in early summer
(May and June), perhaps a reflection of their
regulated environment.
A large share of the price movements, how­
ever, is hard to ascribe to obvious patterns in
the weather or to the timing of holidays. For
example, private education costs exhibit a sin­
gle large seasonal increase in September, the
beginning of the school year, which is offset by
generally small and negative seasonals over the
remaining 11 calendar months. Prices of books
and supplies show large positive seasonal

16

TABLE

3

Deterministic Seasonality in
Individual CPI Components,
1982-1993 (using NeweyWest correction)3
Jan.

Feb.

Mar.

Apr.

May

June

July

Aug.

0.14
0.05
0.36
Cereals
0.09
Meats
0.79
0.29
Dairy
0.29
0.13
Fruits
3.90
0.78
Other food
0.90
0.09
Food away
0.07
from home
0.06
Alcoholic
0.48
beverages
0.30
Shelter
0.17
0.09
Fuel oil
2.55
1.82
Gas and
0.58
electricity
0.19
Other utilities
0.56
0.27
Household
0.00
furnishings
0.12
Housekeeping
0.09
supplies
0.10
Housekeeping -0.05
services
0.06
Men’s
-1.89
apparel
0.11
Women’s
-3 7 1
apparel
0.23
Infants’
-0.91
apparel
0.46
Other
1.06
apparel
0.55
Footwear
-1.27
0.18
Apparel services 0.10
0.08
New vehicles
0.09
0.06
Used vehicles
-0.92
0.26
Motor fuel
-1.07
0.88
Auto repair
0.00
0.04

-0.01
0.03
0.02
0.07
-0.38
0.31
-0.03
0.08
0.51
0.46
0.46
0.15
0.02
0.02
0.46
0.15
0.00
0.04
-1.83
1.72
-0.24
0.23
0.08
0.09
0.32
0.11
0.09
0.08
0.28
0.21
-0.01
0.31
1.45
0.68
1.14
0.82
0.79
0.25
0.24
0.15
0.10
0.07
-0.27
0.12
-0.79
0.26
-1.67
0.69
0.13
0.04

0.00
0.05
-0.16
0.05
0.05
0.23
-0.30
0.06
-0.59
0.53
-0.12
0.06
0.05
0.02
0.12
0.07
0.01
0.10
-2.51
0.63
-0.04
0.18
-0.02
0.10
0.23
0.10
-0.22
0.11
0.03
0.08
1.29
0.12
4.20
0.59
1.01
0.40
-0.09
0.12
1.24
0.17
0.03
0.03
-0.36
0.07
-0.20
0.17
-1.89
0.74
0.05
0.07

0.05
0.05
0.13
0.07
-0.36
0.20
-0.34
0.17
0.71
0.48
-0.14
0.05
0.05
0.02
0.01
0.06
0.02
0.14
-1.56
0.48
-0.38
0.17
0.02
0.10
0.17
0.13
0.22
0.08
0.15
0.20
0.70
0.13
0.64
0.42
0.97
0.54

0.02
0.05
-0.02
0.05
-0.40
0.22
-0.24
0.11
0.00
0.48
-0.15
0.07
0.01
0.02
-0.10
0.06
0.02
0.13
-0.87
0.51
1.46
0.15
-0.05
0.06
-0.20
0.08
0.08
0.12
-0.07
0.05
0.16
0.10
-1.67
0.24

0.05
0.05
0.04
0.06
0.25
0.24
-0.12
0.18
-0.82
0.74
-0.19
0.05
0.00
0.03
-0.09
0.06
0.13
0.10
-0.80
0.54
3.30
0.49
0.05
0.18
-0.20
0.09
0.03
0.03
-0.04
0.09
-1.21
0.20
-2.71
0.43
-0.60
0.29
-0.51
0.39
-0.82
0.18
-0.06
0.12
-0.18
0.08
0.65
0.24

-0.05
0.03
0.06
0.06
0.38
0.28
0.07
0.06
-1.13
0.49
-0.14
0.06
-0.01
0.04
-0.09
0.05
0.28
0.07
-1.37
0.43
0.09
0.17
0.03
0.11
-0.01
0.12
-0.20
0.11
-0.04
0.04
-1.26
0.21
-2.72
0.48
-1.48
0.47
0.48
0.26
-1.12
0.13
-0.14
0.07
-0.27
0.07
0.27
0.21
-0.62
0.49
-0.03
0.04

0.06
0.03
0.11
0.07
0.14
0.24
0.15
0.11
-0.87
0.60
0.03
0.05
-0.02
0.02
-0.15
0.04
0.14
0.04
0.27
0.78
-0.06
0.18
0.06
0.09
-0.27
0.12
-0.28
0.06
-0.05
0.06
0.49
0.21
2.54
0.48
0.60
0.35
0.24
0.15
-0.19
0.16
-0.07
0.07
-0.36
0.09
0.00
0.14
0.19
0.71
-0.04
0.03

CPI— all items




-0.31
0.29
-0.45
0.13
0.04
0.12

0.13
0.20
0.64
0.14
0.00 0.09
0.06 0.07
-0.13 -0.01
0.10 0.08
0.54 0.82
0.16 0.21
1.70 2.57 1.61
1.14 0.37 0.64
0.00 -0.05 -0.04
0.06 0.05 0.04

Nov.

Dec.

0.18 0.01 -0.18
0.04 0.03 0.04
-0.27 -0.15 -0.17
0.05 0.03 0.06
0.01 -0.46 -0.11
0.09 0.16 0.20
0.16 0.23 0.06
0.11 0.13 0.09
-0.79 -0.92 -0.62
0.50 0.19 0.56
-0.13 0.19 -0.48
0.06 0.05 0.07
-0.01 -0.06 -0.05
0.03 0.02 0.02
-0.07 -0.11 -0.34
0.05 0.23 0.07
-0.22 -0.02 -0.23
0.09 0.04 0.06
1.53 2.27 1.39
0.92 0.98 0.44
0.11 -2.76 -2.08
0.14 0.40 0.24
-0.17 -0.06 -0.15
0.06 0.09 0.08
0.25 0.15 -0.17
0.10 0.08 0.09
0.03 -0.05 0.02
0.08 0.10 0.06
0.05 -0.08 -0.13
0.05 0.04 0.03
1.90 1.02 0.18
0.17 0.17 0.07
4.78 1.18 -1.02
0.62 0.39 0.17
0.57 0.06 -0.23
0.26 0.31 0.28
0.24 0.27 -0.40
0.21 0.37 0.21
1.43 1.10 -0.26
0.23 0.31 0.25
-0.06 0.14 0.00
0.05 0.06 0.06
-0.36 0.60 0.91
0.06 0.11 0.10
0.03 0.13 0.00
0.11 0.08 0.10
0.36 0.08 -0.26
0.65 0.63 0.37
0.17 0.01 -0.07
0.05 0.04 0.05

-0.28
0.04
0.07
0.06
0.09
0.26
0.08
0.12
0.61
0.43
-0.24
0.07
-0.04
0.02
-0.33
0.05
-0.30
0.13
0.93
0.55
0.03
0.18
-0.36
0.12
-0.26
0.10
0.18
0.10
-0.06
0.03
-1.37
0.13
-2.97
0.39
-0.83
0.21
-1.75
0.72
-1.05
0.13
-0.12
0.02
0.36
0.12
-0.52
0.17
-1.02
0.45
-0.13
0.08

Sept.

Oct.

R2

0.32
0.28
0.17
0.14
0.30
0.61
0.09
0.21
0.23
0.18
0.77
0.16
0.26
0.17
0.09
0.83
0.82
0.23
0.27
0.68
0.11
0.65
0.31
0.18
0.14

17

T A B L E

3 (cont.)

Deterministic Seasonality in
Individual CPI Components,
1982-1993 (using Newey-West
correction)3

Other transp.
commodities
Other transp.
services
Public
transportation
Medical
commodities
Medical
services
Entertainment
commodities
Entertainment
services
Tobacco
Toilet goods
Personal
services
Books and
supplies
Educational
services
Number of
significant (+)
Number of
significant (-)
Total

Jan.

Feb.

Mar.

Apr.

0.10
0.23
0.30
0.06
0.57
0.18
-0.01
0.04
0.38
0.03
0.21
0.07
0.23
0.10
1.34
0.30
0.18
0.09
0.17
0.06
1.02

-0.07
0.10
-0.19
0.07
-0.16
0.18
0.21
0.07
0.31
0.03
0.10

-0.29
0.13
-0.30
0.07
-0.24
0.14
0.26
0.02
-0.05
0.06
0.16
0.09
-0.14
0.06
-0.34
0.13
0.04

-0.10
0.14
-0.30
0.04
-0.34
0.35
0.16
0.07
-0.17
0.04
0.14
0.07
0.15
0.05
-0.37
0.14
0.24
0.12
0.03
0.05
-0.50
0.05
-0.39
0.04

0 .1 1

-0.21
0.09

0 .1 1

0.04
0.05
0.05
0.13
0.15
0.10 0 .1 1
0.10 -0.18
0.05 0.09
0.26 -0.53
0.07 0.06
-0.37 -0.37
0.07 0.05

12

7

5

4

4
16

10

3

8
13

11

7

May
0 .1 1

0.14
-0.16
0.10
-0.38
0.18
0.01
0.07
-0.19
0.04
-0.21
0.07
-0.27
0.06
-0.20
0.20
-0.26
0.07
0.04
0.08
-0.53
0.05
-0.42
0.07

June

Aug.

Sept.

0.02 -0.29 0.19 0.05 -0.20
0.13 0.13 0.12 0.09 0 .1 1
0.01 0.03 -0.13 -0.45 0.93
0.14 0.10
0.09 0.10 0 .1 1
-0.42 0.22 -0.21 -0.14 0.21
0.43 0.22 0.15 0.19 0.28
-0.09 -0.04 -0.13 -0.09 -0.09
0.04 0.06 0.03 0.05 0.05
-0.12 0.19 0.05 -0.16 0 .0 0
0.03 0.03 0.04 0.03 0.03
0.04 -0.10 -0.03 0.16
- 0 .1 1
0.04 0.04 0.08 0.07 0.07
0.08 -0.04 -0.06 0.26 0.14
0.08 0.07 0.06 0 .1 1
0.07
-0.07 0.89 -0.53 -0.72 -0.14
0.26 0.27 0.23 0.41 0.25
-0.14 0.16 -0.16 -0.12 0 .0 0
0.13 0.15 0.08 0.13 0.08
-0.06 -0.17 0.01 0.07 -0.04
0.05 0.07 0.05 0.06 0.04
2.48 -0.04
-0.37 -0.48 -0.21
0.10 0.06 0.17 0.46 0.04
-0.42 -0.31 0.15 3.38 -0.02
0.07 0.05 0.22 0.58 0 .1 1

3

2

3

2

7

8

7
9

12

9

4
6

12

11

Oct.

5

6
5

11

N ov.

Dec.

0.30 0.19
0.16 0.07
0.44 -0.17
0.14 0.08
0.67 0.23
0.34 0.31
-0.12 -0.05
0.05 0.05
0.03 -0.26
0.05 0.03
- 0 . 1 1 -0.25
0.13 0.06
-0.17 -0.22
0.07 0.07
-0.24 0.33
0.17 0.28
0.08 -0.18
0.10 0 .1 1
0.01 0.01
0.07 0.05
-0.56 -0.54
0.05 0.06
-0.52 -0.50
0.04 0.05
3

2

9

15
17

12

R2

0.12
0.51
0 .1 1

0.25
0.57
0.21
0.30
0.26
0.13
0.14
0.75
0.79

a. Standard errors appear below numbers. Bold type indicates statistical confidence at the 99 percent level.
SOURCE: Authors’ calculations.

adjustments in September and January', coincid­
ing with the start of each school term. New car
models and their attendant price adjustments
are generally introduced in the fall, and in fact,
new car price seasonals are positive and large
in the fourth quarter of the year. Shelter prices
post large positive seasonal adjustments in July
and August, when household migrations are
prominent. And apparel prices show pro­
nounced seasonal price fluctuations that coin­
cide with the fashion seasons— large positive
adjustments in March April and September/
October, and large negative adjustments during
“off-season” periods.
In general, though, there is little commonal­
ity
in seasonal price movements— the aggre­

gate CPI exhibits small seasonal variation rela­


tive to the seasonals in individual component
prices; only food away from home prices
demonstrated less seasonal movement than did
the aggregate CPI from 1982 to 1993.5 In no
month was there a statistically significant deter­
ministic seasonal for a majority of prices (table
3). The most common, statistically significant
seasonal price variations occurred in December,
when 15 of the 36 components had significant,
negative seasonals, against only two significant,
positive seasonals. In January, 12 statistically
significant, positive seasonals were detected
against only four significant, negative seasonals.
■ 5 The aggregate CPI in this study has been constructed using the
36 components and applying 1985 weights, such as in Bryan and
Cecchetti (1994).

18

T A B L E

4

Idiosyncratic Seasonality in 36
CPI Components, 1982-1933
Ratio2

Auto repair
Food away from home
Entertainment services
Apparel services
Personal services
Housekeeping services
Entertainment commodities
Shelter
Other utilities
Medical commodities
Cereals
Toilet goods
Household furnishings
Housekeeping supplies
Medical services
Alcoholic beverages
Dairy
Other transportation commodities
Other food
Meats
Other transportation services
Public transportation
New vehicles
Used vehicles
Tobacco
Other apparel
Infants’ apparel
Books and supplies
Footwear
Educational services
Men’s apparel
Motor fuel
Fruits
Gas and electricity
Fuel oil
Women’s apparel

0.59917
0.76243
1.02518
1.11776
1.19945
1.36387
1.41811
1.75476
2.01226
2.02691
2.62600
2.64553
2.69258
2.89405
3.06386
3.22595
3.65126
4.12955
7.05639
9.20606
11.97717
12.26934
16.25136
19.42488
25.24895
26.94287
45.54596
45.94267
55.30488
69.04402
88.35469
122.08662
124.72690
146.80739
192.29498
532.12456

a. Ratio of idiosyncratic seasonal variance to common seasonal variance.
SOURCE: Authors’ calculations.

Moreover, the items that showed negative sea­
sonal price adjustments during the final two
months of the year were generally not the
same items that tended to rise in price during
the first few months of the following year.
The proportion of the monthly aggregate
price variation accounted for by seasonality"
was similar to that of a large number of its
components, which directly implies that the




unconditional variation in the CPI is also quite
small relative to its components. That is, indi­
vidual goods prices have negative uncondi­
tional and seasonal covariances. These results
contrast with a number of recent observations
on the seasonality of industrial production,
shipments, retail sales, and other real magni­
tudes as documented by Barsky and Miron
(1989), Beaulieu and Miron (1990), and Miron
(1990). Those variables show a positive corre­
lation in seasonality across sectors and coun­
tries, parallel to the comovement in data that is
generally presumed to characterize the busi­
ness cycle.
We can examine the idiosyncratic nature of
seasonal price movements directly using the
linear decomposition of an individual price
movement,y*1/
p .
(2)

p „ = P ? + S ,+

where P f is the average seasonally adjusted
price change, St is the average seasonal price
movement, and sit and e i( are mean zero, idio­
syncratic seasonality and noise, respectively.
That is, aggregate seasonally unadjusted price
movements can be defined as
(3)

P" = 2 w lP ll= P - + Sr

where the u\ s are base-period weights that
sum to unity over all goods n. We can estimate
St directly in the aggregate unadjusted index
and subtract it from the deterministic seasonal
in the individual components to obtain an esti­
mate of the idiosyncratic seasonals. Table 4
reports the ratio of the idiosyncratic seasonality
to the common seasonal variance for each of
the 36 components (var [5;/l /var [5,1). In only
two of the 36 cases—auto repair and food
away from home— was the common price sea­
sonal variance larger than the idiosyncratic sea­
sonal variance. In half of the cases, we find that
the idiosyncratic seasonality7 has more than five
times the variance of the common seasonal.
Our finding that deterministic seasonality in
prices is largely idiosyncratic in nature may be
one reason why studies that have used aggre­
gate price statistics have tended to dismiss the
amount of seasonality in price movement. Fur­
ther, the idiosyncratic tendencies of seasonal
price movements have important ramifications
for the adjustment of such data.

19

TABLE

5

Deterministic Seasonality in the
Seasonally Adjusted CPI, 1982-1993
(using Newey-West correction)
Pre-1994 Procedure_______Post-1993 Procedure
as
t-stat
as
t-stat

Jan.
Feb.
Mar.
April
May
June
July
Aug.
Sept.
Oct.
Nov.
Dec.

0.0016
-0.0003
-0.0011
0.0004
0.0001
0.0003
0.0001
-0.0003
-0.0003
0.0008
-0.0005
-0.0009

R2
Wald
p-value

0.101
44.470
0.0000

3.21
-0.88
-1.93
0.60
0.21
0.41
0.30
-0.88
-0.77
2.35
-1.15
-1.43

0.0008
-0.0005
-0.0008
0.0002
0.0002
0.0007
0.0001
-0.0002
-0.0002
0.0005
-0.0002
-0.0006

1.71
-1.28
-1.31
0.32
0.39
1.10
0.26
-0.50
-0.53
1.73
-0.54
-1.00

0.053
30.590
0.0012

SOURCE: Authors' calculations.

II. Aggregate
Deterministic
Seasonality
The BLS seasonally adjusts the CPI indirectly—
by first filtering the disaggregated components,
then aggregating upward to arrive at the sea­
sonally adjusted price index. Seasonal adjust­
ment at the component level allows the BLS to
capture the wide range of seasonal patterns
that exist in the price data. Moreover, season­
ally adjusting the index in this way ensures that
seasonally adjusted subindexes will aggregate
to the seasonally adjusted aggregate index.
However, not all components are adjusted, as
they must first pass certain statistical criteria;
otherwise, they are introduced into the “sea­
sonally adjusted” aggregate index on an unad­
justed basis.6
Because of the BLS’s selective approach to
seasonal adjustment, 26 of the 60 CPI sub­
indexes (roughly 20 percent of the weighted
index) were left unadjusted prior to January
1994. Yet, because not all of the components
were seasonally adjusted, the BLS may have
inadvertently introduced a seasonal pattern

into the aggregate price series by eliminating


only large seasonal price fluctuations, while
allowing the small, otherwise offsetting sea­
sonal price adjustments to pass into the index
unadjusted. The net result may have been a
residual seasonal variation in the price data that
became conspicuous when the cyclical varia­
tion in prices subsided.
Indeed, over the 1982 to 1993 subperiod,
deterministic seasonality can be detected in the
seasonally adjusted CPI (table 5). Specifically,
seasonally adjusted consumer prices tended to
rise about 2 percentage points (annualized), or
about 50 percent more, during January and
tended to decline by a cumulatively similar
amount during November and December. Such
seasonality accounts for more than 10 percent
of the variation in the seasonally adju sted CPI
over the period.
In an effort to reduce the amount of deter­
ministic seasonality in aggregate consumer
prices, the BLS broadened its seasonal adjust­
ment procedure in 1994 to allow the seasonal
adjustment of a price series, even if it fails to
meet the statistical criteria, if the index at the
next higher level of aggregation meets the crite­
ria for seasonal adjustment.7 As a result of the
new procedure, only 10 of the 60 major sub­
indexes, or about 5 percent of the weighted
CPI, were unadjusted in the seasonally adjusted
CPI in 1994. This procedural change reduced
but did not eliminate the residual, deterministic
seasonality in the adjusted CPI. While no single
month reveals a statistically significant seasonal
at the 5 percent level of significance, Wald tests
of the joint significance of the deterministic seasonals showed seasonality at the 99 percent
confidence level. Moreover, deterministic sea­
sonality still accounts for slightly more than 5
percent of the variation in the seasonally ad­
justed CPI using the new BLS procedures.8

■

6 Specifically, the BLS seasonally adjusts a series if seasonality is
demonstrated by an F statistic greater than 7. While this may seem an
unusually rigorous criterion (the unconditional probability of which is
roughly 10"6), the BLS notes that the F statistic is biased in autocorrelated
data such as these. The BLS further notes that this criterion is commonly
used by other statistical organizations, such as Statistics Canada.
■ 7 In addition, the BLS dropped a rule prohibiting the seasonal
adjustment of a series if it failed the statistical criteria in either of the prior
two years.

■

8 Buszuwski and Gallagher (1995) note that residual seasonality in
the seasonally adjusted CPI appears to originate in the energy components
of the index, specifically fuel oil and natural gas. Moreover, the authors
claim that these price movements are the result of interventions (or trend
adjustments) in the data. Our specification for deterministic seasonality
makes no distinction between different “types” of price movements as long
as they can be observed at the seasonal frequency.

20

TABLE

6

Deterministic Seasonality in
the Seasonally Adjusted CPI and
the Seasonally Adjusted Median
CPI, 1967-1993 (using Newey-West
correction, new procedure)
1967-1993
CPI
as

Jan.
Feb.
Mar.
April
May
June
July
Aug.
Sept.
Oct.
Nov.
Dec.

0.0005
-0.0001
-0.0004
-0.0002
-0.0003
0.0008
-0.0003
0.0000
0.0001
0.0002
0.0000
-0.0003

R2
Wald
p-value

0.010
24.820
0.0090

t-stat

1.46
-0.38
-0.88
-0.48
-0.70
2.12
-0.71
0.00
0.40
1.08
0.02
-0.81

1982-1993
Median CPI
a s.
t-stat

0.0003
-0.0002
-0.0005
0.0001
-0.0002
0.0004
0.0000
0.0004
-0.0002
0.0002
0.0000
0.0000

1.27
-0.86
-1.72
0.43
-0.56
1.26
0.02
1.45
-0.66
0.49
-0.17
-0.53

0.01
15.18
0.174

CPI

«S

t-stat

0.0008
-0.0005
-0.0008
0.0002
0.0002
0.0007
0.0001
-0.0002
-0.0002
0.0005
-0.0002
-0.0006

1.71
-1.28
-1.31
0.32
0.39
1.10
0.26
-0.50
-0.53
1.73
-0.54
-1.00

0.05
30.58
0.0013

Median CPI
a.
c-stat

0.0004
-0.0001
0.0001
0.0005
-0.0003
0.0004
0.0001
0.0000
-0.0006
0.0000
-0.0002
-0.0004

1.45
-0.30
0.22
1.00
-0.64
1.07
0.23
0.28
-1.59
-0.02
-0.48
-1.45

0.05
31.97
0.0008

SOURCE: Authors’ calculations.

Bryan and Cecchetti (1994) demonstrate
how the median in the cross section of con­
sumer price changes reduces idiosyncratic
noise in individual prices and improves the
inflation signal in the aggregate price change
statistic.9 Here, we consider residual seasonality
in the aggregate price index as a special case of
idiosyncratic noise. We test for the existence of
deterministic seasonality in the weighted
median price change calculated from a cross
section of seasonally adjusted data from 36
inclusive components in the CPI. We then com­
pare the results to those of the CPI, similarly
constructed (table 6).
Over the full sample, deterministic seasonal­
ity was found in the seasonally adjusted CPI at
more than a 99 percent confidence level, but at
only an 82.6 percent level of confidence for the
seasonally adjusted median CPI. However, in
the post-1982 subperiod, deterministic season­
ality can be observed in both the CPI and the
median CPI at the 99 percent confidence level.
We tentatively conclude that due to the pre­
dominantly idiosyncratic nature of the determin­
istic seasonality we observe in consumer price




data, the median price change estimate may
reduce the influence of such seasonal noise in
the aggregate monthly price statistics. These
results also have implications for the seasonal
adjustment procedures currently employed by
the BLS. By selectively seasonally adjusting the
component data before constructing the season­
ally adjusted index, the BLS risks inadvertently
introducing idiosyncratic noise into the aggre­
gate index at a seasonal frequency. This poten­
tial problem could be addressed by adjusting
the index after aggregation.
An obvious difficulty that arises from this
approach is that aggregation anomalies can
occur. That is, the weighted sum of the season­
ally adjusted index is unlikely to match the sea­
sonally adjusted aggregate index exactly. Such

■ 9 That paper shows how idiosyncratic price disturbances that are
manifest as an asymmetric distribution of price changes can be reduced by
limited-influence estimators. In that class of estimators, the median has the
highest correlation with past money growth and improves CPI forecasts.

B 0 X 1
The Case of
Stochastic Seasonality
As noted by Miron (1990), stochastic seasonality is not quali­
tatively different or logically separable from stochastic varia­
tion at a nonseasonal frequency.3 Nevertheless, we consider
seasonality of the form
(4)

* , = e + e « ( _ 4,

Seasonality of this type might occur when there is a strong
seasonal price pattern with large adjustment costs. This might
generate intermittent price changes at a seasonal frequency
that persist over a period of a few years. An example might
be adjustments to school tuition that occur in the fall and are
spread out over several school years. Another potential
source of stochastic seasonality is when the seasonal cycle
and the business cycle interact, such that the degree of sea­
sonality depends on the irregular stage of the business cycle.
Such interactions have been demonstrated by Cecchetti,
Kashyap, and Wilcox (1994).
We test for the existence of stochastic seasonality both
independently and jointly with deterministic seasonality for
the unadjusted CPI. In no case, and in neither of the two sub­
periods, were we able to identify a stochastic seasonal
process in the aggregate index. However, several individual
components exhibit stochastic seasonal variation at the 95
percent confidence level, and a few do so at the 99 percent
level (table 7), including educational services, books and sup­
plies, entertainment commodities, motor fuel, apparel serv­
ices, housekeeping supplies, and gas and electricity.
Although we fail to find a significant, stochastic seasonal
process in aggregate prices (a result that has been found else­
where and for other macroeconomic data), we note that
some of the component data exhibit significant stochastic
variation at a seasonal frequency. This result may reveal
those areas where the interaction between the seasonal and
cyclical variation in prices is greatest. Obviously, more work
in this potentially important area is advisable.

anomalies may be a problem for those agen­
cies, like the BLS, that intend the CPI as a costof-living statistic and, therefore, where consis­
tent component estimates are an important
consideration. Consequently, this is not a criti­
cism of the BLS approach per se, but a recom­
mendation for economists who use the CPI as a
monthly inflation guide. As a high-frequency
estimate of inflation, the potential for aggrega­
tion anomalies would seem to be of secondary
importance to the elimination of transitory
noise from the statistic.10

III. Conclusion
In this paper, we reevaluate the evidence of
seasonality in prices in light of the significant
reduction in cyclical price movements that has
allowed the seasonal patterns to become evi­
dent. We find the existence of seasonality to be
substantially greater than previous research has
indicated.
One central conclusion is drawn from this
analysis. Seasonality in consumer prices is pre­
dominantly, although certainly not entirely,
idiosyncratic in nature. This result stands in
contrast to studies that demonstrate a common
seasonal cycle in real economic variables, such
as industrial production and retail sales. Fur­
thermore, given the statistical criteria that the
BLS uses to seasonally adjust component data,
the existence of unadjusted data in the index
may inadvertently allow noise into the price
index at a seasonal frequency. For economists
who are interested in using the index as a highfrequency inflation estimate, this implication
argues in favor of seasonally adjusting the
index after aggregation.

a- A third source of seasonal variation, the seasonal unit root, commonly
specified as x, mx,_ s + e, , was not considered here and has little apparent
standing in the theory or evidence of seasonal processes. An example of a
seasonal unit rcx>t is a calendar effect, such as the number of “paydays” varylng irregularly from month to month depending on the rotation of the sevenday week around the calendar.




■

10 See Buszuwski and Gallagher (1995). An alternative approach
is to seasonally adjust all of the subindexes. This is likely to be inferior as a
noise-reduction technique, however, because seasonal adjustment coeffi­
cients cannot be estimated without error and thus are unlikely to com­
pletely eliminate seasonal noise from the aggregate index.

22

TABLE

References

7

Stochastic Seasonality in the
CPI and Components, 1982-1993
(using Newey-West correction)

Barsky, Robert B., and Jeffrey A. Miron. “The
Seasonal Cycle and the Business Cycle,”
Jo u rn al o f P olitical Economy, vol. 97, no. 3
(June 1989), pp. 503-34.

Without
deterministic
Wald
p-value

CPI—all items

With
deterministic
Wald
p-value

0.4121

0.8138

7.4942

0.0236

19.6336
Cereals
Meats
12.8219
1.5522
Dairy
Fruits
8.9438
Other food
43.4812
Food away
2.1967
from home
Alcoholic
7.0808
beverages
Shelter
49.0183
Fuel oil
2.2181
Gas and
313.7587
electricity
Other utilities
2.8059
Household
4.7049
furnishings
Housekeeping
28.1663
supplies
Housekeeping
3.4370
services
Men’s apparel
23.0618
Women’s apparel 13-5094
Infants’ apparel
0.0967
Other apparel
26.06l6
Footwear
3.0012
Apparel services; 10.9630
New vehicles
7.6641
Used vehicles
4.6747
Motor fuel
1.0181
Auto repair
4.3387
Other transp.
commodities
3.6178
Other transp.
20.7485
services
1.4668
Public transp.
Medical
1.6251
commodities
Medical
services
123.7170
Entertainment
4.4067
commodities
Entertainment
12.4474
services
Tobacco
0.2201
Toilet goods
2.8849
Personal services 2.6919
Books and
293.4063
supplies
Educational
100.6680
services

0.0001
0.0016
0.4602
0.0114
0.0000
0.3334

5.6420
5.4446
1.5523
1.8708
1.9228
0.5165

0.0595
0.0657
0.4602
0.3924
0.3824
0.7724

0,0290

3.7931

0.1501

0.0000
0.3299
0.0000

5.2125
7.1812
9.6267

0.0738
0.0276
0.0081

0.2459
0.0951

7.0030
3.9263

0.0302
0.1404

0.0000

10.8060

0.0045

0.1793

6.0842

0.0477

0.0000
0.0012
0.9528
0.0000
0.2230
0.0042
0.0217
0.0966
0.6011
0.1142

7.7959
6.3310
1.4833
4.1555
1.2125
23.3470
6.2327
8.9065
9.8272
2.0889

0.0203
0.0422
0.4763
0.1252
0.5454
0.0000
0.0443
0.0116
0.0073
0.3519

0.1638
0.0000

2.4884
6.1998

0.2882
0.0451

0.4803
0.4437

2.5277
8.2525

0.2826
0.0161

0.0000
0.1104

2.1021
24.3490

0.3496
0.0000

0.0020

3.6727

0.1594

0.8958
0.2364
0.2603
0.0000

9.46l6
5.8198
4.5603
20.9720

0.0088
0.0545
0.1023
0.0000

0.0000

23.6430

0.0000

SOURCES: Authors’ calculations.




I

Beaulieu, J. Joseph, and Jeffrey A. Miron. “A
Cross Country Comparison of Seasonal
Cycles and Business Cycles,” National
Bureau of Economic Research, Working
Paper No. 3459, October 1990.
Biehl, Andrew R., and John P Judd, inflation,
Interest Rates, and Seasonality,” Federal
Reserve Bank of San Francisco, Weekly Let­
ter No. 93-35, October 15, 1993.
Bryan, Michael F., and Stephen G. Cecchetti.
“Measuring Core Inflation,” in N. Gregory
Mankiw, ed., M onetary Policy. Chicago: Uni­
versity of Chicago Press for National Bureau
of Economic Research, 1994, pp. 195-215.
Buszuwski, James A., and Claire Gallagher. “On
the Use of Indirect Seasonal Adjustment
Methods for the CPI,” U.S. Department of
Labor, Bureau of Labor Statistics, manuscript,
June 1995.
Buszuwski, James A., and Stuart Scott. “On the
Use of Intervention Analysis in Seasonal
Adjustment,” Proceedings of the American
Statistical Association Section on Business
and Economic Statistics (1988).
Cecchetti, Stephen G., Anil K. Kashyap, and
David W. Wilcox. “Do Firms Smooth the
Seasonal in Production in a Boom? Theory
and Evidence,” manuscript, 1994.
Federal Reserve Board. F ederal Reserve Bulletin,
Minutes of the Federal Open Market Com­
mittee Meeting of May 18, 1993, July 1993,
p. 864.
Mankiw, N. Gregory, and Jeffrey A. Miron.
“Should the Fed Smooth Interest Rates? The
Case of Seasonal Monetary Policy ,” National
Bureau of Economic Research, Working
Paper No. 3388, June 1990.
Miron, Jeffrey A. “The Economics of Seasonal
Cycles,” National Bureau of Economic
Research, Working Paper No. 3522, Novem­
ber 1990.

23

Newey, Whitney K., and Kenneth D. West. “A
Simple, Positive Semi-Definite, Heteroskedasticity and Autocorrelation Consistent
Covariance Matrix,” Econom etrica, vol. 55,
no. 3 (May 1987), pp. 703-08.
U.S. Department of Labor, Bureau of Labor Sta­
tistics. BLS H andbook o f Methods, Bulletin
2414 (September 1992), pp. 176-235.
_____ . CPI Detailed Report, January 1994,
pp. 11-15.




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