Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of temporary worker specialist SFN Group (NYSE: SFN) were told "You're fired!" by investors today, falling as much as 21% in intraday trading after the company announced first-quarter results.

So what: SFN did a better job in the first quarter of turning its revenue into profits as it reversed a loss from last year, matching analysts' earnings per share estimates. The company's revenue also moved in the right direction, rising 8.1% year over year to $500 million. That revenue tally, however, was short of Wall Street's $525 million target.

Now what: The look ahead to the next quarter isn't much more encouraging from a top-line perspective. At the midpoint of management's guidance, the company would see 3.5% year-over-year revenue growth during the quarter, which would put sales at $532 million -- once again short of Wall Street's estimates. The company does expect that it will continue to improve profitability, but it appears that investors were expecting growth a bit more robust than what SFN has been able to muster.

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