How do you know if the economy is improving? FRED has plenty of commonly used data to help you. Typically, you’d measure real gross domestic product (GDP)—in particular, its growth rate. This rate is almost always positive. Because population growth is also almost always positive, this isn’t too surprising. So FRED lets you measure real GDP per capita—that is, GDP divided by the population.

But let’s complicate matters, because economies can go through demographic transitions. In fact, because many industrialized countries now face a substantially older population, dividing GDP by the overall population may not be precise either. So, FRED lets you divide GDP by the working age population, age 15 to 64. FRED even lets you refine the measurement by considering only the working age population in the labor force—that is, by excluding those who choose not to work or who cannot work. Finally, FRED lets you measure only those who are actually working by excluding the unemployed still looking for work. (By the way, dividing real GDP by the working population corresponds to labor productivity.)

The graph above shows these five different measures of U.S. economic growth since 1948. Each has its merits, but their growth rates look remarkably similar—so much so that it may not seem worthwhile to distinguish between them. One possible exception is the last series, since the working population fluctuates much more than any of the other population measures.

How this graph was created: All five lines use real GDP, so add real GDP to the graph five times. For line 1, change units to “Percent Change from Year Ago.” For line 2, add the monthly population series, apply formula a/b, and change the units again for this new, transformed line. Repeat this for the remaining lines by searching for and selecting the other population data to divide with. Finally, use the “Format” panel to remove the many axis titles.

Suggested by Christian Zimmermann.