Later Thursday morning, the federal government will release its GDP estimate for the third quarter. One of the things government economists take into account is “seasonality.”

It’s an easy concept to understand, said Guy LeBas with Janney Montgomery Scott. 

“Let’s say I just looked at unadjusted retail sales in Deccember, and it’s up 10 percent from November, I would think the economy is doing spectacularly,” he said. “When in reality that’s just a matter of the calendar.”

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