“The central element of the Penn World Table has always been real GDP per capita, a measure of relative living standards across countries at different points in time.”

—Penn World Table authors Feenstar, Inklaar, and Timmer

FRED recently added data from the 11.0 version of the Penn World Table (PWT), produced by the University of Groningen and the University of California–Davis. This academic data collection provides information about real GDP per capita, as noted above, but also other historical economic conditions around the world. It complements other sources of international data in FRED, such as the International Monetary Fund (IMF), the World Bank, and the Organization for Economic Co-operation and Development (OECD).

How so?

The PWT offers national income accounts–type data converted to international prices and adjusted for differences in purchasing power. Also, the many available PWTs are not data releases like those put out by the IMF, World Bank, or the OECD. The authors call their product “versions” and number them because the methodologies change from issue to issue. It may be more helpful to think of them as “vintages.” Even when there is a correspondence between concepts across versions, there are changes to the methodologies that impact the historical values of the series.

Here’s an example:

Our FRED graph above shows the reported exchange rate between the Sudanese currency and the US dollar between 1950 and 2023: The solid blue line plots data from PWT 7.1 (available for 1950-2010), and the dashed green line plots data from PWT 11.0 (available for 1970-2023). Note that the labels for the data series are different. But, during the period when the two overlap (1970-2010), the majority of values are exactly the same. For a handful of years (1989-1992 and 2010), there are substantial differences in the values, as shown in our FRED graph below.

The PWT authors invite caution when using data from different versions. FRED makes it easy for data users to keep track of PWT versions, and data vintages in general, by suggesting a detailed data citation that includes the date when the data were accessed.

How this graph was created: Search FRED for and select “Exchange Rate to U.S. Dollar for Sudan.” Click the “Edit Graph” button and select the “Add Line” tab to search for “Exchange Rate (market+estimated) for Sudan.” Don’t forget to click “Add data series.”

Suggested by Diego Mendez-Carbajo.