Recalculation of Seasonal Adjustment Factors

Transcription

1 January 1985 Effective with data for January 1985, seasonal adjustment factors have been recalculated to reflect 1984 price movement patterns for stage-of-processing (SOP) and commodity groupings. This routine annual recalculation may affect seasonally adjusted indexes and percent changes from January 198 to the present. Revised seasonally adjusted data for this period, as well as seasonal factors to be used through 1985, are available on request from BLS. Table C shows 1984 monthly seasonally adjusted percent changes for the three major SOP categories calculated with the old seasonal factors, compared with the percent changes for recalculated indexes which incorporate the new seasonal factors. Table C. Percent changes in major stage-of-processing indexes over the month, 1984, seasonally adjusted, using original and recalculated seasonal factors Intermediate material, supplies, Jan Feb Mar Apr... Julv Au a Sept Oct Nov Dec.7 CM CM CM CO CM 1

2 January 1986 Effective with this issue of Producer Price Indexes, seasonal adjustment factors have been recalculated to reflect 1985 price movement patterns for stage-ofprocessing (SOP) and commodity groupings. This routine annual recalculation may affect seasonally adjusted indexes and percent changes from January 1981 to the present. Revised seasonally adjusted data for this period, as well as seasonal factors to be used through 1986, are available on request from BLS. Table C shows 1985 monthly seasonally adjusted percent changes for the three major SOP categories calculated with the old seasonal factors, compared with the percent changes for recalculated indexes that incorporate the new seasonal factors. Table C. Percent changes in major stage-off-processing indexs over the month, 1985, seasonally adjusted, using former and recalculated seasonal factors Intermediate materials, supplies, January... February. July... August... October^ _ 3 2 -

3 January 1987 Effective with this report, seasonal adjustment factors have been recalculated to reflect 1986 price movement patterns for stage-of-processing (SOP) and commodity groupings. This routine annual recalculation may affect seasonally adjusted indexes and percent changes from January 1982 to the present. Revised seasonally adjusted data for this period, as well as seasonal factors to be used through 1987, are available on request from BLS. Table D shows 1986 monthly seasonally adjusted percent changes for the three major SOP categories calculated with the old seasonal factors, compared with the percent changes for recalculated indexes that incorporate the new seasonal factors. Table D. Percent changes in major stage-of-processing indexes over the month, 1986, seasonally adjusted, using former and recalculated seasonal factors Intermediate materials, supplies, January February July August October H

4 January 1988 Effective with this issue of Producer Price Indexes, seasonal adjustment factors have been recalculated to reflect 1987 price movement patterns for stage-of-processing (SOP) and commodity groupings. This routine annual recalculation may affect seasonally adjusted indexes and percent changes from January 1983 to the present. Revised seasonally adjusted data for this period, as well as seasonal factors to be used through 1988, are available on request from BLS. Table C shows 1987 monthly seasonally adjusted percent changes for the three major SOP categories calculated with the old seasonal factors, compared with the percent changes for recalculated indexes that incorporate the new seasonal factors. BLS has improved the seasonal adjustment of selected stage-of-processing indexes. The former method of independently adjusting totals has been replaced for some indexes by the method of adjusting components and adding those seasonally adjusted components to form seasonally adjusted totals. Also, BLS has used an enhanced seasonal adjustment procedure for the major refined petroleum indexes to offset the effects that recent extreme price volatility would otherwise have had on the estimates of seasonally adjusted data for these series. For a general discussion of seasonal adjustment concepts and procedures, see "Seasonally Adjusted and Unadjusted Data" in the Technical Notes section of this report. Table C. Over-the-month percent changes in major stage-of- processing indexes, seasonally adjusted, using former and recalculated seasonal factors, 1987 Intermediate materials, supplies January February July August October

5 January 1989 This edition of Producer Price Indexes reflects seasonal adjustment factors which have been recalculated to reflect 1988 price movement patterns for stage-of-processing (SOP) and commodity groupings. This routine annual recalculation may affect seasonally adjusted indexes and percent changes from January 1984 to the present. Revised seasonally adjusted data for this period, as well as seasonal factors to be used through 1989, are available on request from BLS. Table C shows monthly seasonally adjusted percent changes during 1988 for the three major SOP categories calculated with the old seasonal factors, and compares them with the percent changes for recalculated indexes that incorporate the new seasonal factors. Table C. Over-the-month percent changes In major stage-of- processing indexes, seasonally adjusted, using former and recalculated seasonal factors for 19S8 Intermediate materials, supplies, January February July August October