The web site is the source that we as realtors are told to use. It keeps us from using our own estimates, and getting into legal issues.
The site is easy to use. Just plug in the address in question. If you have any issues just call or email, and I can run the data.
For instance: I have a property in Grand Park on west 23rd. I compared it to a town home in Mandarin, that a client is looking at. The thought being that Mandarin should be a safe area in general. The results when comparing the two were mixed. Grand Park had a higher rate (x2) of burglary but a lower rate of Theft. That leads me to believe that in both areas, care needs to be taken and the use of outside lighting and a security system, to cut down on Burglary in Grand Park, would be advised.
So use an address that you have a feel for whether it is safe or not. Then get the results from the home you are looking at and compare.