Equity real estate investment trusts, or REITs, can be excellent long-term investments, with high dividends and the potential for property appreciation. However, these companies are tough to analyze if you use some of the same metrics you use to evaluate other stocks.

For example, many equity REITs report little or even negative earnings per share, or EPS, quarter after quarter, yet their share prices continue to rise and dividends continue to be paid. Book value is another good example -- many REITs trade for several times their book value, which doesn't really make sense. After all, a company in the business of owning properties should trade for roughly its equity in those properties. 

With that in mind, the slideshow below explains why certain traditional metrics don't work for REITs and presents seven metrics you can use when evaluating an equity REIT that can give you a clear picture of how much money it's making, how cheap or expensive it is, and how financially strong it is.