# Industrial Production and Capacity Utilization - G.17

## Performance Evaluation of the Federal Reserve G.17 (419) Statistical Release — June 2014

## III. Analysis of Revisions

#### III.A. Industrial Production

The monthly indexes of industrial production are first estimated on the basis of incomplete monthly samples; they are revised to incorporate more complete monthly data that become available over the six-month window and then again to incorporate more comprehensive information and annual data in an annual revision that may affect data for several years.

The discussion of the reliability of the total IP index in the Explanatory Note section of the G.17 will continue to highlight the revisions over the previous four-month reporting window until a sufficient history under the new six-month reporting window is available. The average revision to the *level* of the total IP index, without regard to sign, between the first and the fourth estimates was 0.27 percent during the 1987–2013 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 1987–2013 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. The monthly revision history for total IP back to 1972 is available on the Board's public website.

The incorporation of benchmark data into the industrial production indexes at the time of an annual revision has the potential to noticeably change the interpretation of activity in the industrial sector in the year for which the more comprehensive benchmark data cover. For the period from 1992 through 2011, the annual rate of change for total IP has ranged from a drop of 11.2 percent to a gain of 6.4 percent. Over that period, the index prior to the incorporation of manufacturing benchmark data has been essentially unbiased; the average revision to the rates of change upon inclusion of the benchmarks for those years is -0.1 percentage point. In 13 of those 20 years, the absolute value of the revision was less than 1 percentage point; the mean absolute revision for the entire period was 0.8 percentage point, with the maximum upward revision being 1.6 percentage points and the maximum downward revision being 1.9 percentage points.

#### III.B. Capacity Utilization

On a monthly basis, utilization rates are updated to reflect revisions to the underlying production series during the usual reporting window of the production index. From 1983 to 2013, the average revision between the first and second estimates of total industry capacity utilization (except where the second estimate is the publication of an annual revision) was 0.02 percentage point, and the average revision without regard to sign was 0.15 percentage point. Between the second and third estimates, the average revisions with and without regard to sign were 0.02 and 0.11 percentage point, respectively. And between the third and fourth estimates, the average revisions with and without regard to sign were 0.01 and 0.07 percentage point, respectively. The average cumulative revision over a four-month reporting window, if no annual revision occurred during the window, was 0.04 percentage point, and without regard to sign, the average cumulative revision was 0.21 percentage point.

On a longer-term basis, the revisions to the measures of capacity utilization were examined by comparing the capacity utilization rates published in the last 13 annual revisions of industrial production and capacity utilization with their pre-revision levels. For each of the 16 annual revisions, the revisions to the operating rates for total industry were calculated for the final quarters of the three most recent years: For example, in the annual revision published in March 2014, the total industry capacity utilization rate revised down 0.3 percentage point in the fourth quarters of each year from 2011 through 2013. Over the last 16 years, the average revision to most recent three years of total industry capacity utilization has been -0.05 percentage point; the average revision without regard to sign has been about 0.42 percentage point.