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: Harris (NYSE: HRS) dropped 10% in intraday trading today after fiscal third-quarter revenue fell well short of the consensus forecast.

So what: Revenue of $1.41 billion grew 6% from the year-ago quarter but was a whopping 7% shy of the consensus forecast of $1.51 billion. Non-GAAP EPS of $1.16 fell 11% year over year but beat the consensus estimate by a penny.

Now what: Rising production costs and a slowdown in U.S. defense spending were behind the earnings decline from the prior year and raise concerns about the outlook. With just the current quarter left in fiscal 2011, management reiterated fiscal year guidance of non-GAAP EPS of $4.80 to $4.90, suggesting the consensus estimate of $4.89 is overly optimistic. The company appears to be relying on acquisitions to improve EPS -- always a risky strategy.

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Fool contributor Cindy Johnson does not own shares of any company named above. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.