Month Labor Review Article

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International Price Program U.S. Export and Import Price Indexes

Month Labor Review Article

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Price Measures of New Vehicles

Price measures of new vehicles:
a comparison
The Consumer Price Index, the Producer Price Index,
and the International Price Program all analyze price changes
in new vehicles; however, these indexes’ movements are only weakly
correlated because of methodological differences in sampling, pricing,
the analysis of incentives, and other aspects of survey design
Maria Bustinza
Daniel Chow
Thaddious Foster
Tod Reese
David Yochum

Maria Bustinza,
Thaddious Foster,
Tod Reese, and David
Yochum are
economists in the
Office of Prices
and Living Conditions
and Daniel Chow is
an economist in the
Office of Field
Operations, Bureau
of Labor Statistics.
E-mail:
[email protected],
foster.thaddious@bls.
gov,
[email protected],
[email protected]

he automobile industry is a vital and
dynamic component of the U.S. and
global economies. Faced with competition spurred by technological advances
and global demand, the industry has attracted significant attention from policymakers,
the media, unions, and businesses in the
last several years. In the United States, the
automobile industry employed more than 1
million workers in 2006.1 U.S. production
during this period was 11.4 million units,2
and U.S. consumers purchased 16.5 million
cars and trucks. At the same time, foreign
manufacturers with factories in the United
States have significantly increased their
presence in this country.3 In recent years,
U.S. automakers have been facing restructuring, financial stresses, and competitive
challenges to their traditional market shares.
Furthermore, U.S. consumers, exposed to
record high gasoline prices, are being offered a growing choice of hybrid-fueled
vehicles. As the range of vehicle models,
features, and options has grown, consumers
have been gaining access to more and better information about these characteristics
via the Internet. In this competitive market,
price incentives offered by both domestic
and foreign automakers to U.S. consumers
have become the industry norm.
The automobile industry presents many
challenges to anyone trying to measure accurately the average price change of new ve-

hicles. Over the years, the Bureau of Labor
Statistics (BLS) has often been asked why its
three programs that measure changes in new
vehicle prices—the Producer Price Index
(PPI), Consumer Price Index (CPI), and International Price Program (IPP)—have often
trended differently despite the fact that they
measure the same industry.
This article explains the differences among
the three programs’ methods of index calculation, analyzes these differences, and elucidates the implications of the new passenger
car price indexes. Through detailed examples,
the article conveys how sampling, pricing,
consumer and dealer incentives, exchange
rates, and model year changeover with quality
adjustments are handled differently by each
program. This article shows that the discrepancies among the indexes are largely the result of methodological differences among the
programs; however, the article also emphasizes that these methodological differences have
an economic basis and are usually a product
of differences in the scope and measurement
objective of each index.

Overview of recent price trends
Chart 1 offers a graphical overview of the
Bureau’s new vehicle price index series from
January 2000 to June 2007. Visual analysis
of the chart reveals the striking variation in
the behavior of these indexes. Specifically, the
Monthly Labor Review • July 2008 19

Price Measures of New Vehicles

Chart 1. BLS new vehicle indexes, not seasonally adjusted, January 2000–June 2007
[Rebased, Jan 2000 = 100]
Index
108
106
104

Index
108

PPI Passenger cars
CPI New cars
IPP Export Series Automobiles and other motor
vehicles including minivans, 4-dr speciality vehicles
IPP Import Series Motor vehicles
designed to transport people

106
104

102

100

Jan
Oct
Oct
Oct
2000
2001
2002
2003
NOTE: PPI data March 2007–June 2007 are preliminary.

Oct

chart shows that the two IPP series did not experience the
same degree of annual price volatility as the PPI and CPI, and
that the two IPP series increased during this period while
the PPI and CPI slightly decreased. These variations are attributable to the different measurement objectives among
the price indexes, to the different program methodologies,
and to the prevailing economics of the new vehicles market
during this period.
The relative stability of the IPP new vehicle export and
import series can be explained by the absence of rebates and
incentives offered to consumers of new model vehicles. The
IPP series strictly measure prices between overseas agents,
domestic producers, and importers. These prices do not
reflect the price decreases used for promotions by dealerships and, therefore, they produce relatively steady monthly
changes. The PPI and CPI include rebates and incentives,
along with the price increases that accompany the introduction of new model year vehicles towards the latter half
of the year, and these contribute to more volatility from
month to month.
Comparing the PPI and CPI new-vehicle price indexes,
the PPI series is more volatile than the CPI series because
its sample transitions completely to the new year’s mod20 Monthly Labor Review • July 2008

2004

Oct

2005

Oct

2006

Oct

Jun
2007

els in October, typically resulting in a large, spiking price
increase. The CPI’s transition to the newer models is done
over a span of months, producing smoother increases in
the index while the transition is occurring. The impact
of the transition to the new models is less pronounced
in the IPP series because it is not affected by changes in
incentives and, as a result, does not exhibit the associated
rise and fall of prices.
The divergence in the long-term trends of the IPP indexes (which have increased) compared with the PPI and
CPI (which have decreased) is also the result of the inclusion of incentives in the PPI and CPI. Because of the highly
competitive nature of markets for new vehicles during the
period of the study, the value of manufacturer-offered incentives hit record levels about a dozen times prior to leveling off in 2005. These attempts to appeal to the marketplace
through lower prices mean that as the value of the incentives increased, the true prices of new vehicles fell, resulting in end-of-year prices that were lower than the previous year’s prices. Compounded, these decreases produced
downward trends in the PPI and CPI, while the IPP indexes
remained insulated from the competitive pricing seen at
the manufacturer-to-dealer and the consumer levels. The

types of vehicles included in the various measures, as well
as the number of models tracked in the respective market segments, also contribute to the trend differences. The
IPP Import Index includes a larger proportion of luxury
vehicles and the IPP Export Index includes a larger proportion of sport utility vehicles (SUVs), both of which are
relatively more expensive types and models of vehicles
and contribute to the upward trends of those indexes. The
balance of this article explains in more detail these differences among the new vehicle indexes.

Methodological differences among the programs
Differences in the types of prices that each program tries
to measure contribute to a disparity in price index movement among the indexes. Chart 1 displays this disparity,
showing that it is especially strong in the short run. The
PPI measures the average change over time in the selling
price received by domestic producers, the CPI measures
changes in the estimated transaction price consumers pay
to auto dealers, and the IPP measures changes in import
and export prices paid at the U.S. border minus shipping
and customs fees. Cars manufactured abroad but sold in
the United States are in scope for the IPP Import Index
and the CPI, but out of scope for the PPI. Cars manufactured and sold in the United States are in scope for the
PPI and CPI, but not for the IPP. Cars manufactured in the
U.S. and sold abroad are in scope for the PPI and the IPP
Export Index, but not for the CPI. Before examining the
movements of the new-car indexes, this article describes
differences among them in sampling, pricing, treatment
of model year changeover, quality adjustment, and price
incentives. Such differences help explain the differences
in the movements of the indexes and are referenced in
the section that discusses index movements. A complete
comparison of index methods for the three programs is
shown in the appendix.
The indexes chosen for this study were selected because
the types of vehicles covered by each index are similar,
although there are some differences. The PPI’s passenger
cars index and CPI’s new cars index provide a similar
comparison. The closest match in the IPP’s export series
is Automobiles and other motor vehicles including minivans, 4-dr specialty vehicles. The IPP import series closest
match is Motor vehicles designed to transport people.4
Although the IPP indexes include a wider variety of vehicles, all of these indexes include cars, and the PPI and
CPI include cars exclusively. Therefore, this article refers to
them as “car” indexes and not “vehicle” indexes.

Sampling. The scope of the PPI includes automobile manufacturers with factories located in the United States. Every 5
years, the pool of available manufacturers is resampled, and
BLS representatives visit the sampled companies to request
their participation in the survey. All of the manufacturers’
domestically produced vehicles are in the sample universe.
Vehicles with the highest revenue have a higher probability
of selection using the probability-proportional-to-size sampling technique. Selection of the vehicle options is based on
the percentage of customers selecting an option installed on
the model, which is known as the penetration rate. The PPI
sample is generally smaller than the CPI sample.
The CPI new car pricing area universe is the entire urban
United States. Its area sample consists of 87 geographic
primary sampling units (PSUs), which are urban areas across
the Nation. The Telephone Point-of-Purchase Survey asks
households in each PSU about their new vehicle expenditures to establish which dealerships to visit for pricing.
Selected dealers are visited by a BLS representative to disaggregate the universe of new cars5 sold to consumers on
the basis of dollar volume sales in order to identify and
choose cars for data collection from the sampled dealerships. Specifically, this is done by selecting a unique car
make, followed by a model within that make, and lastly a
unique trim level within the model. Given that car models tend to have various styles with different equipment,
the trim level is used to distinguish among the available
performance levels or equipment package options. For
example the “EX” and “LX” are trim levels for a Honda
Accord model. Once a trim level is selected, the dealer
is asked to reference the invoice of the last car sold with
that trim level in order to complete the vehicle description
including options. The CPI sampling process usually yields
three distinct vehicles with equipment options to price in
each sampled dealership. In total, about 1,500 vehicles are
priced at 500 dealerships; about half of the vehicles are
cars. The sample of dealerships is replaced at the rate of 25
percent each year.
The sample of exports for the IPP is derived from U.S.
Census Bureau data from shippers’ export declarations,
and the sample of imports is derived from consumption
entry documents.6 The IPP employs the probability-proportional-to-size technique to determine which companies compose the sample. After companies are selected,
the IPP chooses individual vehicles for pricing by disaggregating according to model, trim level, and options.
Each vehicle stratum is sampled every 2 years on an ongoing basis. This ensures that the IPP’s sample captures
current market trends. The IPP’s motor vehicle index is
different from both the CPI’s and PPI’s motor vehicle inMonthly Labor Review • July 2008 21

Price Measures of New Vehicles

dexes because it includes a broader category of vehicles.7
Comparison of the sampling methods reveals three
distinctions. The first is the types of vehicles included in
the samples. The CPI and PPI only include cars, whereas
the IPP includes cars, minivans, sport utility vehicles, and
trucks. The second involves manufacturing location; the
CPI includes both U.S.- and foreign-produced cars, the
PPI sample represents U.S.-produced cars, the IPP Export
Index represents U.S.-produced cars, and the IPP Import
Index represents foreign-produced cars. The third factor is
the smaller sample sizes of the PPI and IPP compared with
the CPI’s sample size. This is due to the extent of manufacturers’ participation, which determines for how many
vehicles manufacturers will provide data and how often
they provide those data.
Pricing. The PPI measures prices received by manufacturers for the new cars they produce and sell. The price
data are net prices, which are prices paid to the manufacturer inclusive of the manufacturer’s discounts to the
buyer. The PPI national office collects prices from manufacturers via a monthly survey, and the prices reflect sales
for the Tuesday of the week containing the 13th of the
month.
The type of price usually collected for the car index is
a dealer net price (that is, what the dealer pays for the
Table 1.

vehicle). The dealer net price reflects sales from the manufacturer to the dealer and deducts rebates and low rate
financing given by the manufacturer. If these incentives
are only available in some regions or on some transactions, a national average value for all sales of that model
is calculated. Price or discount information received after
an index is first published is incorporated into the final
index released four months after original publication. If
discount information is not available before the index is
calculated, then a first-published index is released based
on all data available at the time. Table 1 provides an example of the types of prices and price adjustments applicable to each of the price indexes and shows how they
are used to estimate reported prices.
The CPI measures the price of a new car to the consumer at the retail level. Typically, new car prices are
negotiated between the buyer and the dealer, so the CPI
reflects the negotiated price by estimating a transaction
price on the basis of recent sales including markups,
rebates, and/or concessions. Also included in CPI pricing but not included in IPP and PPI pricing are charges
for the new vehicle’s transportation to the dealer, dealer
preparation of the vehicle, and sales taxes as shown in
table 1.
Prices in the CPI are collected bimonthly in most metropolitan areas. However, prices in New York, Los Angeles,

New vehicle pricing comparison

Prices and price adjustments

Reported price......................................................

PPI

CPI

IPP Export

IPP Import

Domestically
produced cars

Domestically and
foreign-produced cars

Cars, golf carts,
SUVs, mobile homes,
minivans

$18,750
$21,550
Prices
1
Border price....................................................
( )
(1)
Dealer net price.............................................
20,000
(1)
Retail base price............................................
(1)
22,000
Transportation charge................................
(1)
800
Dealer preparation.......................................
(1)
100
Optional equipment...................................
1,000
1,100

Subtotal................................................
21,000
24,000
Price adjustments
2
2
Consumer rebate..........................................
(1,000)
(1,000)
2
Low rate financing.......................................
(500)
(1)
2
Dealer rebate
(750)
(3)
2
Concession......................................................
(1)
(2,000)
Duty . ..........................................................…
(1)
(1)
Taxes ............................................................…
(1)
550
Freight..............................................................
(1)
(1)
1
2
3

Not applicable.
This figure is subtracted from the subtotal.
Included in concession.

22 Monthly Labor Review • July 2008

$20,600

$20,075

20,000
(1)
(1)
(1)
(1)
1,000
21,000

(1)
(1)
(1)
(1)
(1)
(1)
2
(400)

(1)
(1)
(1)
(1)
2
(525)
(1)
2
(400)

and Chicago are obtained monthly. Price data collection
occurs throughout the entire month and is done by BLS
representatives assigned to various dealerships. Typically,
three distinct cars are priced in a sampled dealership. If a
particular model and trim level was not sold in the past 30
days, it is deemed temporarily unavailable for pricing. If at
least one car of a particular model and trim level was sold,
the estimated transaction price is based on sales of that car
over the past 30 days; average markup, rebate, and/or concession are estimated. The CPI’s use of the 30-day pricing
reference period and pricing throughout the month are
techniques that may contribute to a lag in the reflection
of price change that does not apply to the PPI and IPP, for
which prices collected reflect one specific reference day.
The concession is the negotiated segment of the consumer transaction price with the dealer; concessions are
common, which means that consumers typically do not
pay list price for a new car. Typically, list prices do not
change from month to month. An example of the impact
a concession has on a new car price in the CPI versus the
impact it has on a new car price in the other car indexes
is illustrated in table 1. Pricing starts with the retail base
price and then adds transportation charges, options, and
dealer preparation charges. Then the price is adjusted for
additional markup and discounting due to concession
and/or rebate. These markups, concessions, and rebates are
all estimated on the basis of sales over the past 30 days for
the model and trim level in question.
Rebates and concessions are major contributors to the
monthly CPI car price index movements. These two price
discounts work hand-in-hand; if the rebate spikes up the
concession may fall, and if the rebate is reduced, the concession may rise. This tends to offset the impact of new
rebate offers.
The International Price Program produces measures
of price change for goods and services imported into the
United States and exported from the United States. By
conceptual definition, the IPP seeks to capture import
prices at the port of entry and export prices at the port
of exit. A variety of types of prices are eligible for inclusion, including intrafirm prices as well as trade between
unrelated parties.
These import and export price indexes are utilized to
deflate various foreign statistics produced by the Census
Bureau and the Bureau of Economic Analysis. In order
to be compatible with these measures, IPP price data are
adjusted for duty and freight costs. As illustrated in table
1, these adjustments are unique to these measures and are
not used for the CPI or PPI price data. Another factor that
applies to the IPP and not to the PPI or CPI is the use of

exchange rates. Although the majority of manufacturers
who trade overseas price their products in U.S. dollars,
some traders price vehicles in local currencies. To convert
foreign currencies to U.S. dollars, the IPP receives exchange rate conversion factors for the major foreign currencies from the University of British Columbia Pacific
Exchange Rate Service each month. Although exchange
rates fluctuate over the course of the month, the IPP uses
the average monthly exchange rates from this source.
The IPP national office collects prices monthly directly
from U.S. international traders and manufacturers. Data
used in these indexes are collected via mailed forms or
via the Internet. The reference date for data used in IPP
indexes is the first day of each month. The IPP revises its
data 4 months after the initial release in order to account
for data that were not collected in time for index calculation but have since been collected. Although the IPP collects prices on the first day of each month, late data that
arrive within the 4 month time frame are used in calculating revised measures. Table 1 shows that the CPI and PPI
prices are subject to more adjustments than are the IPP
indexes, which helps to explain the differences in volatility
and long-term trends among the indexes described in the
earlier discussion of chart 1.
Model year changeover and adjusting for quality change. The
CPI and PPI programs both began making price adjustments to account for quality changes in new vehicles with
the introduction of the new vehicle models in 1966 (1967
models). Every year, typically in late summer and early
fall, automobile and truck manufacturers introduce updated models to the market. In most cases, the new cars
are similar enough to the previous models that the prices
of both models can be compared with each other without
the application of an adjustment. However, if a manufacturer significantly changes the quality or functionality of a
new car, BLS applies an adjustment to factor out the price
change associated with the change in quality.8
The three BLS price programs use information gathered
directly from car manufacturers and secondary sources to
estimate the values for quality change adjustments. Each
program follows the same basic guidelines for new model
introduction; however, there are a few differences in how
certain quality changes are handled. BLS places new car
quality characteristics into five categories. All three programs make adjustments for the changes in each of the
categories, with one exception noted in the second category. The first category includes changes in the safety of
a car that are either federally mandated or proven to be
effective. These include airbags, seatbelts, brake systems,
Monthly Labor Review • July 2008 23

Price Measures of New Vehicles

seat designs, back-up alerts, and crumple/crash zones.
The second category covers mandated changes that
affect the healthfulness of the outside environment,
such as emissions improvements as legislated by State
governments or the Federal government. In this category, there is one notable difference among the programs—the treatment of mandated pollution control
measures by the CPI. Whereas the PPI and IPP make
quality adjustments for changes arising from air-pollution mandates, beginning in 1999 the CPI stopped
making such adjustments. The basis for the decision
was that price changes that derive from mandated
product changes and that affect only public goods, like
air quality, are essentially taxes levied on the purchasers of new cars and should be reflected as price increases in the index. This is consistent with the CPI’s
practice of including changes in taxes when they affect
the prices paid by consumers for market goods.9
The third category pertains to changes made to mechanical or electrical features. This category includes
changes in steering, braking, engine efficiency, and transmission systems, among others. The fourth category includes changes in design or materials that affect the durability or strength of an item. Examples include the switch
to halogen headlamps, to platinum tipped spark plugs,
and to flexible body panels.
The final category encompasses changes that affect
comfort or convenience. These upgrades include redesigned seat belts, remote door locks, navigation systems,
and flexible body panels, as well as changes in storage
capacity. BLS does not make quality adjustments for style
changes, such as pin striping or leather-wrapped steering
wheels. Adjustments also are not made for manufacturer
quality claims that are improvements of failed or defective components.
The quality adjustment values provided by the
manufacturers are based on resource costs. BLS defines
resource costs as all direct and indirect costs, including research and development, incurred in the manufacture or purchase of components and the assembly
and installation associated with an equipment change,
including the manufacturer’s mark-up. Resource cost
factors into both the PPI and IPP. For the CPI, this value is marked up to the retail price level. In general, a
quality change tends to be a small portion of the entire
new vehicle price. Based on the model year changeovers from 2000 to 2007, the yearly average per-car
retail quality adjustment ranged from $25 to $310,
with an average of $125.
Chart 1 illustrates that October is typically the
24 Monthly Labor Review • July 2008

month when the PPI and the IPP export samples switch
completely to the new model year and in which the
quality adjustments are applied.10 Note that the IPP
introduces the majority of the new model year export
vehicles into the Export Index in October. In some
cases, however, new model introduction occurs when
more than half of the cars sold are the new model.
Import vehicles are introduced when more than half
of the cars imported are the new model. The introduction period for IPP import vehicles is typically August through November. The similar average October
increase between the Import and Export indexes is
purely coincidental given the typical 2-month interval
between the times when new vehicles are introduced
in each respective index. The CPI always introduces
new models into the index when more than half of the
cars sold are the new model. The introduction period
for the CPI is typically from September in the current
year to February the following year.
Although the three price programs employ different
methodologies for introducing new vehicle models into
the index, new model introduction generally results in
price increases for each program. The following table
illustrates 1-month percent changes from September
to October for the PPI, CPI, and IPP indexes. The PPI
shows much larger percentage increases each October
than do the CPI and the IPP indexes. The PPI showed
an average October increase of 5.6 percent from 2000
to 2006.

Year

PPI

Average.............. 5.6

2000................ 6.1
2001 .............. 1.4
2002 .............. 9.0
2003 .............. 8.4
2004 .............. 6.6
2005 .............. 3.0
2006 .............. 3.5

CPI

0.5
-.3
.6
.9
.4
1.1
1.5
.6

IPP
Export

0.4
.2
.3
1.0
.4
.2
.3
.3

IPP

Import
0.4
.4
.4
.7
.9
.1
.2
.4

During the years listed in the table, the increases in
the PPI ranged from 1.4 percent in 2001 to 9.0 percent
in 2002. The CPI increased an average of 0.5 percent.
During the study period, both IPP export and import
motor vehicles increased 0.4 percent on average. The
larger magnitude of the PPI October increases is due
to the complete model year changeover to new models
with few or no incentives. For the CPI, the sample of
cars priced in October is a mix of current and newer
model years. For example, in 2006, the CPI car sample

mix was 42 percent 2007 models and 58 percent 2006
models. The newer model year cars reflect price increases, whereas the older models reflect price decreases caused by discounting to clear out the older models.
The only exception to the October increases from
2000 through 2006 was the slight 0.3-percent decline
in the CPI in October 2000, which reflected how the
CPI prices a larger portion of the older models during
October, a month known for heavy discounts. The 1month percent changes for a program may be larger
in one year than the next year because of an array of
issues. However, the differences among the programs
in a given year are primarily due to each program applying quality adjustments at its own time.
Incentives. Understanding the use of incentives in the
passenger cars indexes is important because incentives are
responsible for most of the monthly changes in price other than model year change. Incentives are tracked by the
CPI and PPI but not by the IPP, thus contributing to the
differences in the long-term trends seen in chart 1. In the
context of this article, incentives are programs offered by
the car manufacturers to stimulate sales. The three most
common programs are consumer rebates, dealer rebates,
and low interest rate financing. Some manufacturers also
provide additional rebates for specific customer segments
such as first-time buyers, students, and the military.
Consumer rebates are provided by manufacturers as an
incentive directly to the customer at the point of sale to
reduce the net price of the car. Consumers normally elect
to credit this consumer cash rebate as a down payment
against the new car’s purchase price. Manufacturers may
also provide cash incentives directly to dealers, known as
dealer rebates. The dealers may or may not choose to pass
some part of this rebate on to their customers.
There are many instances in which customers are allowed to choose either a cash rebate or a low interest financing offer. In still other cases, customers may benefit
from both the cash rebate and the low interest financing offer in combination. It is important to note that the
low interest rate financing quoted in the offer is normally
based on the top customer credit tier, and as a result not
all consumers are eligible for this best rate.
The PPI includes consumer rebates and dealer cash rebates as well as low interest financing offered by manufacturers. Ideally, the PPI would include only the incentives
in effect on the pricing date. However, some data may
only be available as monthly averages for each vehicle line.
Manufacturers provide the PPI program with information
on their cost of providing low interest financing loans,

the value of cash rebates, and the acceptance rate for the
incentives. In cases when incentives are offered on only
some vehicles for sale, such as when regional incentives
or programs allowing the customer to choose either low
interest rate financing or a cash rebate are offered, the PPI
program calculates a national average value for the incentives on the vehicle in question.
The CPI includes an estimated average of the consumer
rebates available over the past 30 days for each model in
the sample. An estimated average is used because rebate
amounts may vary over the collection period and different
types of rebates may be offered, such as those for the military or recent graduates. Beginning in January 1999, the
CPI stopped measuring finance charges on vehicle loans.
This change was made on conceptual grounds.11
The CPI is the ratio of the cost of a set of items in one
period to its cost in another period. Financing the consumption of an item indicates the purchaser has decided
to consume that good today by forgoing the consumption
of other goods in the future. This “price” the consumer pays
in order to choose current consumption over future consumption is the interest rate on the loan. Forgoing future
consumption in exchange for consumption today causes
the financed good to become, in a sense, a financial debt or
liability. However, the CPI is principally focused on estimating actual consumption at retail prices in the most current
period only; this gives a clearer picture of the cash-value
prices consumers would pay at the retail outlet.12
Financing motor vehicles is arguably different from other forms of retail financing because vehicle financing terms
can influence negotiations over the final purchase price. On
rare occasions a dealer will offer “special financing” terms
without explicitly offering a reduced price alternative. In
these cases dealers would presumably be willing to negotiate an equivalent price concession to purchasers who either
do not select or do not qualify for the financing deal. The
CPI respondents are asked to provide an estimate of this
concession.
The IPP does not include incentives in its index calculation. The primary reason is that companies providing
vehicle price data to the IPP are principally multinational
companies that trade from one subsidiary to another. For
example, a sedan may be produced in Japan by a Japanese manufacturer and then traded to a subsidiary in the
United States. In this case, it is more cost effective for one
subsidiary simply to adjust prices rather than offer incentives, which are much more costly to implement.
Whether incentives are included in the prices used by
the price indexes is ultimately a question of scope. The
PPI reflects consumer rebates, dealer rebates, and low inMonthly Labor Review • July 2008 25

Price Measures of New Vehicles

terest rate financing because these incentives affect the
prices producers receive for their vehicles. The CPI does
not directly reflect low interest rate financing, but it does
include an average of consumer rebates and dealer rebates
in the negotiated price because these incentives directly
affect the prices consumers pay for an automobile. The
IPP does not include any incentives because they are not
a factor in the derivation of prices paid at the border for
imports and exports.

Index comparisons
This section examines historical index data from 2000
to 2007 to reveal trends and statistical relationships in
the BLS new passenger car indexes. To measure how the
programs’ indexes diverge from or track each other, the
indexes are analyzed using three approaches. The first approach is a graphical treatment describing the movements
and trends across each program. The second approach uses
qualitative explanations highlighting key methodological
issues, industry events, and shifts in consumer demand,
rebates, or dealer incentives. The third approach is a comparison of correlations between the data series.
Index trend analysis. As seen in chart 1, the PPI trended
downward from 2000 to 2007, while the CPI trended
downward from 2000 through mid-2003 and then began
an upward trend. The PPI is characterized by relatively
sharp monthly movements. There are visible short-term
co-movements in both series; in fact, the evidence indicates that the two series also trend together in the long
run but are weakly correlated.
Chart 2, which presents the 1-month percent changes
in the new cars indexes from February 2000 to June 2007,
more clearly shows the sharper PPI movements compared with the movements of the other data series. The
PPI spikes coincide with model changeover each October.
This is followed by sharp drops each November representing the resumption of incentives offered from manufacturers to dealers. Unlike the PPI, the CPI monthly percentage movements generally stay within the 1-percent
range. Furthermore, the CPI October percentage increases
tend to lag behind the PPI increases in time because of the
CPI’s gradual phase-in of new model introductions with
less generous incentives and rebates.
As shown in chart 1, the long-term trends of the IPP
export and import vehicle series diverge from the PPI
and CPI series during the sample period. The CPI and PPI
trend downward, whereas the IPP indexes exhibit upward
trends. These divergences can be partially attributed to dif26 Monthly Labor Review • July 2008

ferences in the product compositions among the indexes.
The IPP Import Index is composed of a higher proportion
of luxury vehicles in comparison with the CPI and PPI
new vehicle indexes. Recent trends indicate that import
nameplate manufacturers (foreign firms producing in the
United States) prefer to build lower cost vehicles in the
United States and import luxury vehicles from overseas.
The sales of higher priced vehicles in this market segment
have grown each year since 2000. This demand level appears to be less elastic and has allowed import manufacturers to regularly raise prices on most import models in
this class of vehicle.
In an analogous trend, a noteworthy factor affecting
export price movement during this period has been strong
demand in foreign markets for domestically produced
sport utility vehicles. Domestic SUV production and sales
to both domestic and international customers have risen
steadily from 2000 to 2007 and contributed to the longterm rise in the export price index.
Also contributing to the differences in long-term
trends between the IPP indexes and the PPI and CPI is inclusion of incentives in the PPI and CPI but not in the IPP.
As mentioned in the “Overview of recent price trends”
section, the highly competitive nature of markets for new
vehicles during the period of the study has resulted in
substantial incentives being offered at the manufacturerto-dealer and the consumer levels, and these incentives
are reflected in the PPI and CPI indexes. The IPP index,
in contrast, does not include incentives, because companies providing vehicle price data to the IPP are principally
multinational companies that trade from one subsidiary
to another.
Chart 2 illustrates that in the short term the IPP
import and export indexes often exhibit differing index
movements. These short-term differences can be partially
attributed to differences in how new models are introduced into the import and export indexes. For the Import Index, few new vehicles are introduced over a longer
period of time, resulting in modest index changes during new model introduction. In contrast, for the Export
Index, 100 percent of new model introduction occurs in
October. This produces generally smaller increases in the
Import Index and less frequent but larger increases in the
Export Index.
Qualitative analysis. In 2001, the September 11 terrorist attacks on the United States and start of the war in
Afghanistan affected the PPI. The typical October spike
for the PPI was nearly absent due to extensive special low
finance deals intended to offset slumping sales over this

Chart 2. Events occuring among 1-month percent changes for new vehicles indexes, February 2000–June 2007
[Rebased, January 2000 = 0]
Index
8.0

PPI

CPI

IPP Exports

IPP Imports

Index
8.0

7.0

6.0

6.0
Impact of
9/11,
Afghanistan
war begins

5.0
4.0

Iraq war
begins
March
2003

5.0
4.0

3.0

2.0

1.0

0.0

–1.0

–2.0
Record
incentives
July 2004

–3.0
–4.0

Employee
discounts
June 2005

Feb
2000

Oct Feb
2001

Oct Feb
2002

Oct Feb
2003

Oct Feb
2004

period. The CPI, by contrast, which does not reflect low
finance incentives, registered a relatively normal increase
for the new 2002 models. The IPP also increased slightly
because of the introduction of new models.
The PPI’s large October 2002 spike occurred as automakers
sought to return to aggressive model year switchovers, after a
relatively weak previous year, by raising 2003 model prices and
offering fewer incentives compared with the summer months.
This was followed in November by a sharp price decline of
2.6 percent in the PPI, whereas the CPI moved up to its November peak. Both the IPP Import Index and the IPP Export
Index rose nearly 1 percent in October 2002, reflecting the
new model switchovers, but the imports series moved slightly
higher at this time. This reflected an increase of approximately
0.5 percent by the Euro versus the dollar.
The March 2003 spikes in the PPI and CPI were attributed to the start of the Iraq war, and they reflected
economic uncertainty among manufacturers, dealers, and
consumers. In April of that year, the PPI fell as incentives
were reinstated. Car importers and exporters kept prices
stable because their shipments were not affected.
In April 2004, the IPP Export Index exhibited its largest
upward movement of the year, reflecting vehicle exporters’

Oct Feb
2005

Value
pricing
August
2005

Oct Feb
Oct Feb Jun
2006
2007

–2.0
–3.0
–4.0

general ability to raise prices during the year for current models. Record incentives were introduced in July 2004, causing
both the PPI and CPI to decline substantially. This record incentives level was exceeded in September. Automakers, however, were able to quickly cut incentives and raise prices on
new models between September and October 2004, resulting
in the PPI’s highest level since January 2000. (See chart 1.) In
January 2005, the PPI rose to an even higher level as manufacturers again raised prices and cut incentives.
In 2005, employee discounts were offered to all consumers. These discounts were later replaced with “value pricing”13 as another means to attract consumers. As a result
automakers were able to clear out the 2005 model year cars,
and this in turn contributed to the drop in the CPI prior to
the model year changeover. Later in 2005, automakers chose
to move up some model year introductions from October
to September. These early model year introductions caused
both the CPI and PPI to increase in September. The following October, however, the normally large PPI spike was
diminished because of the shift in introduction month.
During 2006 and 2007, the new car market continued
to be very price competitive. Demand for fuel-efficient cars
was strong because gasoline prices remained high. The generMonthly Labor Review • July 2008 27

Price Measures of New Vehicles

ally unchanging trend of the CPI appeared to hold. The July
2006 PPI decline was due to summer low interest financing
promotions, which the CPI does not reflect. In September
2006, the PPI posted an upward movement attributed to a
drop in incentives unusual for that time of the year. The following October, the PPI experienced greater-than-normal
incentives offered by manufacturers to dealers on new 2007
models, moderating the expected October spike.
Correlation analysis. Previous discussions and graphical
analyses indicate that there are substantial differences among
the methodologies and also among the movements of the
new vehicle price indexes. These differences are primarily the
result of each program’s unique measurement objective. In
spite of these methodological differences, graphical analysis
indicates that the new vehicle indexes often exhibit similar
movements. Correlation analysis can be used to determine
the degrees of similarity or difference between the new car
indexes. If strong positive correlations exist, then the indexes
reflect common industry dynamics despite their unique
methodologies. Weak or non-existent correlations would be
evidence that the differing index methods result in largely
dissimilar data movements. It is possible for correlations to
be spurious or coincidental, however. Strong correlations that
persist for long periods are more strongly indicative of a true
relationship than are weaker correlations.
The table below presents correlations between the 1month percent changes of the PPI, CPI, and IPP indexes
calculated using data from January 2000 to June 2007, not
seasonally adjusted. Statistically, the relationships between
the PPI, CPI, and IPP indexes do not appear to be strong.
The correlation coefficient for the PPI and CPI is about 0.38,
which is less than the correlation between the PPI and the
IPP Export Index (0.44) and also less than the correlation
between the PPI and the IPP Import Index (0.49). The correlation coefficients between the CPI and IPP are the weakest. This indicates that the CPI and IPP series diverge more
in their monthly movements than do the PPI and IPP series,
which often use similar data.

Index
PPI
CPI
PPI.................
CPI. ...............
IPP Export.....
IPP Import.....

1 …
.379
.439
.487

…
1
.221
.053

28 Monthly Labor Review • July 2008

IPP
Export

…
…

1
.442

IPP

Import

…
…

To further detect whether strong relationships exist
among the series, the indexes were seasonally adjusted
to remove regularly occurring cycles throughout the
year that might obscure the relationships between the
indexes.14 When correlations of the 1-month percent
changes from the resulting seasonally adjusted indexes
are compared—as illustrated in the following table—the
correlations among the series are weak. For example,
the PPI–CPI correlation falls from 0.38 to 0.08, and the
relatively weak 0.49 correlation between the PPI and IPP
Import Index drops by more than half to 0.22 after seasonal adjustment. Evidenced by the larger values in the
previous table, it is clear that cyclical movements, such as
the regular October model year changeovers, account for
much of the correlations in the not seasonally adjusted
data. In summary, the correlations provide statistical
evidence that significant data divergences exist among
the car indexes but that the indexes share some common
features.

Index
PPI
CPI
PPI................. 1 …
CPI. ............... .083
IPP Export..... .165
IPP Import..... .22

…
1
.082
–.136

IPP
Export

…
…
1
.25

IPP

Import

…
…

THE THREE BLS PRICE PROGRAMS—the PPI, CPI, and
IPP—all publish price indexes for new cars. It is often
assumed that these indexes trend similarly, but this article has shown that this assumption is not accurate. A
graphical comparison of the indexes shows differences
in both month-to-month volatility and in long-term
trends for the 2000 to 2007 period. The article explains
these graphical differences by outlining the differences
in scope and measurement objectives among the indexes.
Where these differences in scope translate into methodological differences, the article discusses how the differing methods in areas such as sampling, data collection,
the treatment of rebates and incentives, and adjusting for
quality change may produce indexes that differ greatly in
both the short and the long term. Major economic and
political events are cited and their impact on the indexes
is discussed. Finally, correlation analysis is employed in
order to show that the correlations between all pairs of
indexes are weak.

Notes
1
This study uses the automobile manufacturing industry classifications 3361, 2, and 3 from the North American Industrial Classification
System. For employment data in this industry, see Current Employment Statistics, U.S., all employees, on the Internet at http://data.bls.
gov/cgi-bin/srgate (visited July 22, 2008). To retrieve the data, type the
code CEU3133600101 into the series id(s) box.

See www.census.gov/mtis/www/mtis.html (visited June 10,
2008).
2

3
For the purpose of this article, import vehicles are those that are
built outside U.S. borders.

Codes for the four indexes are: PPI Passenger cars (Commodity
code 1411031), CPI New cars (SS45011, CPI-U, U.S. city average), IPP
Export Series, Automobiles and other motor vehicles including minivans, 4-dr specialty vehicles (HICP code 8703), and IPP Import Series
Motor vehicles designed to transport people (HICP code 8703).
4

The CPI includes new motorcycles, though they represent a minor
weight.
5

The IPP employs the Harmonized Classification System (by industry); BEA Classification (by end use); and the NAICS System (by industry). For more information, see the BLS Handbook of Methods, chapter 15, on the Internet at www.bls.gov/opub/hom/homch15_a.htm
(visited July 15, 2008).
6

7
The IPP universe of vehicles includes automobiles, SUVs, golf carts,
all terrain vehicles (ATVs), and motor homes. The IPP vehicle sample,
like the PPI sample, utilizes the probability-proportional-to-size sampling technique.
8

The three price programs follow the BLS procedures called “Guide-

lines for Quality Adjustment of New Vehicle Prices,” on the Internet at
www.bls.gov/cpi/cpiautoqaguide.pdf (visited July 15, 2008).

See Dennis Fixler, “Treatment of Mandated Pollution Control
Measures in the CPI,” CPI Detailed Report (Bureau of Labor Statistics,
Sept. 1998).
9

In instances when new model introduction does not occur in October, each price index will include the new model vehicle when data
is received from the manufacturer. This is commonly referred to as a
mid-model year launch.
10

“Changing the Item Structure of the Consumer Price Index,”
Oct. 16, 2001, on the Internet at www.bls.gov/cpi/cpiwl001.htm (visited June 10, 2008).
11

Examples for which the CPI normally does not seek to measure
interest payments include houses, items whose prices are based on layaway plans, or any other financial transaction or instrument.
12

13
A pricing discount is provided by the manufacturer and lowers
the listed sticker prices; these are often offset by a reduction in dealerto-consumer incentives.
14
BLS publishes seasonally adjusted indexes for the PPI and CPI
vehicles series cited here but does not produce seasonally adjusted estimates for the corresponding IPP indexes. Published seasonally adjusted
data from the PPI and CPI are estimated using the Census Bureau’s
X-12-ARIMA method. The seasonal data are subject to strict production requirements and are revised over several years. Thus, a simplified
seasonal adjustment analysis was applied in this study to compare all
four series. For more information on seasonal adjustment in BLS, see
http://stats.bls.gov/cpi/cpisameth.htm (visited June 10, 2008).

Monthly Labor Review • July 2008 29

Price Measures of New Vehicles

Appendix: Detailed comparison of the PPI, CPI, and IPP
International Price Program
(IPP)

Producer Price Index
(PPI)

Consumer Price Index
(CPI)

Product objective

Measure changes in producer
selling prices.

Measure changes in consumer
prices.

Measure changes in import
and export prices.

Product coverage

Passenger cars and light trucks
(14,000 lbs. or less) produced in
the United States

New passenger cars and light
trucks purchased by consumers
for personal use. Included are
both domestic and import manufacturers. The number of vehicles
in the sample fluctuates. In
December 2006 the sample included 539 dealerships pricing
762 cars and 729 trucks.

Harmonized 8703–automobiles, SUVs, golf carts, and
ATVs, both diesel and gasoline.

Classification
system(s)

Industry-based indexes are classified
according to the North American
Industry Classification System (NAICS). Commodity-based indexes are
classified according to an internal
BLS system.

Internal BLS system

Samples are based on the Harmonized System (HS). Indexes are
published on the basis of HS, Bureau of Economic Analysis (BEA)
End Use, and North American
Industry Classification System
(NAICS).

Calculation

Modified Laspeyres formula

Hybrid Index—Laspeyres and Geo- Modified Laspeyres formula
metric Means

Sampling frequency

Every 5 years

Outlet sample is updated every
year by 20–25%

Every 2 years

Sample universe

All motor vehicle producers with
manufacturing plants in the
United States

All new vehicles sold in the U.S. for
personal use. The geographic areas
for sampling are 87 primary sample
units (PSUs).

Vehicle importers and exporters
(primarily marketing units and
manufacturers)

Includes vehicles
manufactured
outside the U.S.

Yes, if sold in the United States

Import index: yes. Export
index: yes given item clears
U.S. customs first.

Weighting

Index divided into cells using
census value of shipment data
for each cell.
Within cells, vehicles are weighted
by manufacturer.

Reflects expenditures reported by
households for the Consumer Expenditure Survey for the years 1993–1995.
A 2-year rotation beginning in 2002.
New vehicle weight in CPI is 4.983%.

Based on trade dollar values
provided by U.S. Customs (imports) and U.S. Census Bureau
(exports)

Vehicle discontinued

Vehicles are not substituted midsample unless they are discontinued.

Vehicles are not substituted unless
they are no longer available for sale.

Vehicles are not substituted midsample unless they are discontinued or phased out.

Transitioning to a
new model year

Transition to the new model year
starts when the new vehicles are
first shipped to dealers. This usually occurs in October.

The transition occurs when the new
model year vehicle’s dollar volume
sales exceed those of the old model
year for the tracked vehicle. This is
determined separately for each vehicle at each dealer. This roll-over
usually starts in September and can
last 4 to 6 months.

For exports, the transition occurs in October in some cases or
when new models exceed 50 percent of models exported in the
remainder of cases. For imports,
transition occurs when over 50%
of the vehicles are new.

SAMPLE

OVERVIEW

File Type	application/pdf
File Title	Price measures of new vehicles: a comparison
Subject	Price measures of new vehicles: a comparison
File Modified	2008-08-05
File Created	2008-08-05