Sources and Techniques Used in the Construction of Annual CPI, 1774 to the present.

The CPI series is a composite of many series. From 1917 onward, official U.S. CPI series, those of the Bureau of Labor Statistics (BLS), are used. For 1978 to the present, the series is CPI-U (consumer price index for all urban consumers). For 1917-1978 (the latter year used for linking the series), the series is CPI-W (consumer price index for urban wage earners and clerical workers). For 1914-1917, the series of Paul Douglas is taken in place of the BLS series, because of improvements that he makes. The resulting series is linked to the composite series of David and Solar for 1774-1914. References to the data sources and complete details on construction of the CPI series are in What Was the Consumer Price Index Then? A Data Study.