Behind the myth of the ‘spring slump’

April 29, 2013, 1:00 PM UTC
What spring slump?

FORTUNE – When Wall Street learned Friday that the U.S. economy grew slower than expected during the start of the year, it renewed talk that we may be in for another “spring slump,” if not a “spring swoon.”

Whatever you call it, a slowdown in the economy has emerged every spring for the past three years. Growth starts the year off strong, but then just as investors and traders think it’s gaining steam, growth suddenly detours into a serious slowdown. By summer, analysts really start worrying, only to — psych! — see better growth by fall.

Since March, signs of a spring slowdown have emerged — the latest was Friday’s report from the Commerce Department, which showed that GDP grew at a 2.5% annual rate between January and March. While lower than the widely expected 3.2% growth, it’s still markedly stronger than the previous quarter’s 0.4% growth.

And last month, another sign: Hiring slowed sharply, with the economy adding only 88,000 jobs, the lowest monthly gain since last June.

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While Wall Street might wonder if we’re in for another slump this year, the slowdown may actually be a total myth. It may have more to do with issues with the way economic data is calculated than what’s really going on in the economy, says Gary Evans, global head of equity strategy at HSBC.

After the U.S. economy collapsed during the final quarter of 2008, the huge drop in growth was interpreted as a seasonal adjustment. And so from then on, data for the first quarter in subsequent years was automatically adjusted higher. While this might have smoothed out the numbers from dramatic lows, it may have also made GDP growth during the second quarter appear weaker than what it really was. What’s more, GDP growth during the spring might look lower because the Federal Reserve announced major plans to stimulate the economy at the end of the summers in 2010 and 2012.

To be sure, this doesn’t change some real headwinds we face this year — namely, higher taxes and federal spending cuts, known as the sequester, that kicked in in March as part of a move to reduce the U.S. deficit. While consumers appear unfazed, at least for now, the cuts could weigh heavier later this year when government agencies furlough employees and reduce contracts. Whatever the reason for a spring slowdown, HSBC forecasts growth will slow sharply during the second quarter to 0.9% and 1.1% during the third quarter.

If a slump does indeed materialize, the economy is at least somewhat better off to handle one than it did three years ago.