A lot of it is driven by appraisers reading reports like this and undervaluing properties when you try to exit.  

@Vincent Crane  you may want to look at small multi family those usually hit your numbers easier and your competition is all numbers driven...

Noticed that it looked empty, so I began looking at the data online (and driving by the property to look for signs of life).

If you feel that the seller will not be able to successfully sell the property on their own, demonstrate the difficulty you think they will have to them with data such as comparable properties that aren't selling. 

I think there's lots of variables and that I care more about where yields are going to be in 5 years than where they've been the past 5 years (for buy and hold).But, anything you put together that helped me compare different areas more easily than looking at raw census and raw area government data would be interesting.

That $95 is talk, text, data, navigation, and insurance.

Saw a post on city-data forums about BP and that is how I am here :)I always had/have an inclination to enter into Real Estate business since I was a kid.

You want to either have access to MLS based sales comp data or have a realtor get you the information. 

(not raw data) But the data is reported to come from the Houston Association of Realtors (HAR)SFH supply is 2.8 months, (2014 = 2.9 months)DOM increased 7-days YOYMedian listing price is up 7%, but median sales price is not.

I would think that something like an algorithm can be created, though, since most of this information and data is available in government records. ...Something to think about for the techies I guess, if it isn't already out there. :)