As to crime some cities offer online programs that collate information from the local Police and Sheriff departments (Crimemapper is one such program) anc make these available to the public on the City/Town website. If something like this isn't available to you in your area, simply go into to the local police office and ask. How's the unemployment rate? If it's high then this may indicate both a likelihood of higher crime as well as future problems with home values.
There's no simple way to answer your questions, it takes some diligence on your part to make a good informed decision.
If the community in question possesses none of these attributes, then a real analysis must be completed. This is what pros get paid for...the REAL analysis. Consult a professional near you. Ratios, trends, mobility, development, press and nearby graffiti can all influence value.
Forecasting, by it's very nature requires more transparency regarding your objectives. You can understand that if this is the LAST home you EVER intend to buy, the objectives are clearly different from the anticipation of a doing career development time (mid-management) in preparation for the bump up in six years.
Best of Success to you,
Annette Lawrence, Broker/Associate
Remax Realtec Group
Palm Harbor, FL