![]() Skip to Content Release dates | Historical data | Documentation Current Monthly Release Other formats: ASCII | PDF (144 KB) Supplemental Monthly Release Other formats: ASCII | PDF (144 KB) Annual Revision Release Other formats: ASCII | PDF (150 KB) Industrial Production Explanatory Notes Coverage.The industrial production (IP) index measures the real output of the manufacturing, mining, and electric and gas utilities industries; the reference period for the index is 2002. Manufacturing consists of those industries included in the North American Industry Classification System, or NAICS, definition of manufacturing plus those industries–logging and newspaper, periodical, book and directory publishing–that have traditionally been considered to be manufacturing and included in the industrial sector. For the period since 1997, the total IP index has been constructed from 303 individual series based on the 2002 North American Industrial Classification System (NAICS) codes. These individual series are classified in two ways: (1) market groups, and (2) industry groups. Market groups consist of products and materials. Total products are the aggregate of final products, such as consumer goods and equipment, and nonindustrial supplies (which are inputs to nonindustrial sectors). Materials are inputs in the manufacture of products. Major industry groups include three-digit NAICS industries and aggregates of these industries–for example, durable and nondurable manufacturing, mining, and utilities. A complete description of the market and industry structures, including details regarding series classification, relative importance weights, and data sources, is available on the Board's web site. Changes in output for the market and industry groups are summarized in table 1 and the levels of output (in index form) are shown in table 4. Special aggregates, that highlight the relative importance and contributions of several key industries, such as high-technology and motor vehicles, are summarized in table 2 and table 5. Source data. On a monthly basis, the individual indexes of industrial production are constructed from two main types of source data: (1) output measured in physical units and (2) data on inputs to the production process, from which output is inferred. Data on physical products, such as tons of steel or barrels of oil, are obtained from private trade associations and from government agencies; data of this type are used to estimate monthly IP wherever possible and appropriate. Production indexes for a few industries are derived by dividing estimated nominal output (calculated using unit production or sales and unit values) by a corresponding Fisher price index; the most notable of these fall within the high-technology grouping and include computers, communications equipment, and semiconductors. When suitable data on physical product are not available, estimates of output are based on either production-worker hours or electric power use by industry. Data on hours worked by production workers are collected in the monthly establishment survey conducted by the Bureau of Labor Statistics. The factors used to convert inputs into estimates of production are based on historical relationships between the inputs and the comprehensive annual data used to benchmark the IP indexes; these factors also may be influenced by technological or cyclical developments. The annual data used in benchmarking the individual IP indexes are constructed from a variety of source data, such as the quinquennial Censuses of Manufactures and Mineral Industries and the Annual Survey of Manufactures, prepared by the Bureau of the Census; the Minerals Yearbook, prepared by the United States Geological Survey of the Department of the Interior; and publications of the Department of Energy. Aggregation Methodology and Weights. The aggregation method for the IP
index is a version of the Fisher-ideal index formula. (For a detailed
discussion of the aggregation method, see Federal Reserve Bulletin
February 1997
and
March 2001.)
In the IP index, series that measure the
output of an individual industry are combined using weights derived from
their proportion in the total value-added output of all industries. The IP
index, which extends back to 1919, is built as a chain-type index since
1972. The current formula for the growth in monthly IP (or any of the
sub-aggregates) since 1972 is the geometric mean of the change in output
(I), and, as can be seen below, is computed using the unit value added
estimate for the current month (pm) and the estimate for previous month: The IP proportions (typically shown in the first column of the relevant tables in the G.17 release) are estimates of the industries' relative contributions to overall growth in the following year. For example, the relative importance weight of the motor vehicles and parts industry is about 8 percent. If output in this industry increased 10 percent in a month, then this gain would boost growth in total IP by 8/10 percentage point (0.08 x 10% = 0.8%). To assist users with calculations, the Federal Reserve's web site provides supplemental monthly statistics that represent the exact proportionate contribution of a monthly change in a component index to the monthly change in the total index. Timing. The first estimate of output for a month is published around
the 15th of the following month. The estimate is preliminary (denoted
by the superscript "p" in tables) and, beginning with the release of
March 2008 data, subject to revision in each of the subsequent five
months as new source data become available. (Revised estimates are
denoted by the superscript "r" in tables.) For the first estimate of
output for a given month, about 70 percent of the source data (in
value-added terms) are available; the fraction of available source
data increases to 84 percent for estimates in the second month that
the estimate is published, 98 percent in the third month, and 98
percent in the fourth month. Data availability by data type, based on
the four-month reporting window used in 2007, is summarized in the
table below:
NOTE: The physical product group includes series based on either monthly or quarterly data. As can be seen in the first line of the table, in the first month, a physical product indicator is available for about half of the series (in terms of value added) that ultimately are based on physical product data (27 percent out of total of 54 percent). Of the 27 percent, about two-thirds (18 percent of total IP) include series that are derived from weekly physical product data and for which actual monthly data may lag up to several months. On average, quarterly product data are received for the third estimate of industrial production. Specifically, quarterly data are available for the second estimate of the last month of a quarter, the third estimate of the second month of a quarter, and the fourth estimate of the first month of a quarter. About 3 percent of the source data for monthly IP–all physical product measures–are available too late for direct inclusion in the current index and are incorporated at the time of an annual historical revision. Seasonal adjustment. Individual series are seasonally adjusted using Census X-12 ARIMA. For series based on production-worker hours, the current seasonal factors were estimated with data through September 2006; for other series, the factors were estimated with data through at least June 2006. Series are pre-adjusted for the effects of holidays or the business cycle when appropriate. For the data since 1972, all seasonally adjusted aggregate indexes are calculated by aggregating the seasonally adjusted indexes of the individual series. Reliability. The average revision to the level of the total IP index, without regard to sign, between the first and the fourth estimates was 0.26 percent during the 1987-2006 period. The average revision to the percent change in total IP, without regard to sign, from the first to the fourth estimates was 0.21 percentage point during the 1987-2006 period. In most cases (about 85 percent), the direction of change in output indicated by the first estimate for a given month is the same as that shown by the fourth estimate. Rounding. The published percent changes are calculated from unrounded indexes, and may not be the same as percent changes calculated from the rounded indexes shown in the release. References The annual revision published in December 2004 is described in an article, Industrial Production and Capacity Utilization: The 2004 Annual Revision, in the Winter 2005 issue of the Federal Reserve Bulletin. A description of the aggregation methods for industrial production and capacity
utilization is included in an article in the
Federal Reserve Bulletin , vol. 83 (February 1997), pp. 67-92.
The Federal Reserve methodology for constructing industry-level measures of capital is
detailed in Capital Stock Estimates for Manufacturing Industries: Methods and Data by Mike Mohr and Charles Gilbert (1996).
Industrial Production--1986 Edition contains a more detailed description of the
other methods used to compile the industrial production index, plus
a history of its development, a glossary of terms, and a bibliography. The
major revisions to the IP indexes and capacity utilization since 1990 have been
described in the Federal Reserve Bulletin (April 1990, June 1990, June 1993,
March 1994, January 1995,
January 1996,
February 1997 ,
February 1998,
January 1999,
March 2000,
March 2001,
March 2002, and
April 2003).
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