Historical Revisions (2017)> > > > >
January 11, 2018
In January of each year, the Federal Reserve Bank of Philadelphia revises historical data for the Manufacturing Business Outlook Survey after calculating new seasonal adjustment factors. Because survey responses are characterized by seasonal patterns, new seasonal factors are calculated annually based on the addition of a complete year of data.
While this year's revisions altered levels of the indexes for most months, the general pattern of month-to-month change in most series was similar (see the charts and links to the revised historical data below).
For the final two months of 2017, the current activity index was revised upward from its previously reported readings. For November 2017, the current activity index was revised upward slightly to 24.3 from the previously reported reading of 22.7. For December 2017, the index was revised upward from 26.2 to 27.9.
Seasonal adjustments were based on the U.S. Census Bureau's Census X-12 program, and seasonal factors for the 12 months of 2018 are being projected using the X-12 ARIMA method.
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