The FRED Blog sometimes taps into ALFRED, the archive of historical versions (or vintages) of FRED data. Today’s post does just that to discuss how the Bureau of Economic Analysis (BEA) periodically updates its quarterly and annual gross domestic product (GDP) figures to produce more accurate and complete figures of overall economic activity.
The ALFRED graph above shows seven different vintages of real GDP for the second quarter* and third quarter of 1991. The vintage dates included in the series names are the dates when the BEA released a comprehensive update to the data series. While a data revision incorporates newly arrived source data to paint a more complete picture of current or very recent economic conditions, a comprehensive data update reflects changes in economic and statistical standards applied to the whole economic record.
Comprehensive updates typically take place every five years, give or take a year or two, depending on business cycle conditions. On those dates, the BEA also updates its GDP statistics by moving forward the reference year for its inflation adjustment and price measures. The legend on the left axis of the ALFRED graph lists the reference year for the seven comprehensive updates to the real GDP series available in our database: 1987, 1992, 1996, 2000, 2005, 2009, and 2012. As the general price level rises over time, each successive bar is taller than the previous one. However, absent substantial changes to the types of economic activity being measured, the compounded annual rates of growth of real GDP record very small differences (see example here).
At the time of this writing, the latest comprehensive update was released in July 2018. Although the date for the next hasn’t been announced yet, it could be completed as early as 2023. Whenever the BEA releases those updated data, FRED will make them available through its website and ALFRED will add another vintage to its series repository.
* Why did we include the second quarter of 1991 in the graph? FRED went live online on April 18, 1991, the second quarter of that year.
How this graph was created: Search ALFRED for “Real Gross Domestic Product.” By default, ALFRED shows a graph with two sets of bars: the most recent vintage and the prior vintage. Add additional vintages by using the “Add Line” tab and select the date of the desired vintage from the “or select a vintage” dropdown menu. Change the start date and the end date above the graph to customize the number of data points shown.
Suggested by Diego Mendez-Carbajo.
