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 for-profit educator Strayer Education (Nasdaq: STRA) plummeted 25% in early Monday trading after reporting a 20% drop in new enrollments so far in the school year.

So what: While continuing enrollments managed to rise 10%, Mr. Market is obviously more concerned about how the dismal new enrollment number will impact Strayer's future results. Of course, with Strayer being one of the bellwethers in the education space, it's no surprise that smaller players like American Public Education (Nasdaq: APEI), Bridgepoint Education (NYSE: BPI), and Capella Education (Nasdaq: CPLA) are also down big today on the news.

Now what: Even with today's whopping plunge, Fools should continue to stay far away from Strayer, which has only a one-star rating in our CAPS investing community. Given the drop in new enrollments, Strayer updated its previous business model for 2011 -- which assumed a 13% jump in annual student enrollment and stable operating margins -- to include a range of estimates. With that rosy-looking scenario now as Strayer's "best-case" outcome and a "worst-case" that assumes a 5% decline in enrollment growth along with shrinking operating margins, Strayer doesn't seem like the smartest bet going forward.

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