The way today’s preliminary estimate of second-quarter gross domestic product is presented may sow confusion. Ben Casselman explains how to understand the number:

In the United States, G.D.P. isn’t reported as a simple change from one quarter to the next. It’s reported as an annual rate. (Technically a seasonally adjusted annual rate.) Think of it this way: If this rate of change held steady, this is how much G.D.P. would grow or shrink over a full year.

A negative 35 percent annual growth rate would mean economic output was 10.2 percent smaller in the second quarter than in the first. (It’s not as simple as dividing the annual rate by four, because growth rates compound.)

Looking at things on an annualized basis can be useful, because it makes it easy to compare data collected over different time periods. You’ve probably done a version of this calculation yourself! “OK, if I cut out my $4 daily latte, that would save me $1,000 a year.”

But when annual rates get applied to short-term or one-off changes, they can be misleading.

Right now, the economy is experiencing a lot of short-term swings. The developments are real and important — but it doesn’t make much sense to annualize them.

For that reason, in our coverage tomorrow, The Times plans to emphasize the simple, nonannualized change from the first quarter to the second. We’ll still give the annualized number for those used to seeing it that way, plus other numbers as relevant, such as year-over-year change.

This approach will make the second quarter change look milder than if we had used the annualized figure. We plan to do the same thing next quarter, when it will (presumably) make the rebound look smaller. But in both cases, we believe it will more clearly communicate what is happening in the economy.

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