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 certain months, the general pattern of month-to-month change in most series was similar (see Charts and links to revised historical data below). The largest one-month revision for the current activity index was for October — the index was revised downward 4 points, from a previously reported level of 19.8 to 15.6.
For December 2013, the current activity index was revised downward slightly to 6.4, from a previously reported reading of 7.0. The six-month future activity index was revised upward slightly to 44.8, from a previously reported reading of 44.0.
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