In January of each year, the researchers at the Federal Reserve Bank of Philadelphia calculate new seasonal adjustment factors for the Manufacturing Business Outlook Survey using data through December of the previous calendar year.
- These new seasonal factors generate minor revisions to the seasonally adjusted data for prior years.
- A one-year forecast of the new seasonal factors is used to adjust new survey data for each forthcoming month of the current year.
Due to atypical volatility at the onset of the pandemic and the long, steep recovery period that followed, we have excluded data from 2020 and 2021 from our analysis of seasonal factors. To revise seasonal adjustment factors for prior years and forecast factors for the current year (2026), we:
- calculated new seasonal adjustment factors using the U.S. Census Bureau’s X-12 procedure based on data from January 1976 through December 2019, appended with data from January 2022 through December 2025.
- calculated factors for each month of 2020 and 2021 by interpolating between each month of 2019 and 2022.
- applied revised seasonal adjustment factors to the nonseasonally adjusted data from January 1986 through December 2025.
- forecasted seasonal factors for each month of 2026 using the X-12 ARIMA method.
Find the complete history data for all series.
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