Each business day, TheStreet.com Ratings compiles a list of the top five stocks in five categories -- fast-growth, all-around value, large-cap, mid-cap and small-cap -- and publishes these lists in the Ratings section of our Web site. This list is based on data from the close of the previous trading session. Today we focus on mid-caps. These are stocks of companies that have market capitalizations of between $500 million and $10 billion that rank near the top of all stocks rated by our proprietary quantitative model, which looks at more than 60 factors. The stocks must also be followed by at least one financial analyst who posts estimates on the Institutional Brokers' Estimate System. They are ordered by their potential to appreciate. Note that no provision is made for off-balance-sheet assets such as unrealized appreciation/depreciation of investments, market value of real estate or contingent liabilities that might affect book value. This could be material for some companies with large underfunded pension plans. Strayer Education ( STRA) is a for-profit post-secondary education services corporation. The company's mission is to make high quality, post-secondary education achievable and convenient for working adults in today's economy. Our buy rating for Strayer has not changed since March 2003, and is based on a variety of strengths that include the company's revenue and net income growth and its largely solid financial position. For the first quarter of fiscal 2008, Strayer's revenue rose 21% year over year due to increased enrollment and a 5% tuition increase that went into effect in January 2008. As a result, earnings per share improved 26%, while net income increased 25% from $18.81 million in the first quarter of fiscal 2007 to $23.52 million. Another favorable sign for the company is that it is debt free, resulting in a debt-to-equity ratio of zero.