Historical Revisions (2018)> > > > >
January 10, 2019
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).
The current general activity index was revised upward over the first four months of the year and revised downward over the last four months. For December 2018, the index was revised slightly, from 9.4 to 9.1.
Seasonal adjustments were based on the U.S. Census Bureau's Census X-12 program, and seasonal factors for the 12 months of 2019 are being projected using the X-12 ARIMA method. Adjustments were calculated based on the most recent 50 years of data.
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