Statistically speaking, more than 80% of your deals will come at or beyond the 5th mailing. 

I'm currently finding what seems like potential cities to invest in, finding basis statistics such as population growth, crime rates, vacancy rates, avg prices, etc. and comparing it in excel. 

Look at the statistics for the area. 

I can tell you statistically speaking your odds are much greater if you get a college degree in a decent paying field.Study computer science, engineering, accounting, finance etc.

Even though the actual owner was evicting them.I have developed more of a science to screening tenants based on statistics and my experience. 

There is no "article" you will read in the media that has any accurate information or statistics about the business of flipping as it occurs in the real world.There will be better times, there will be worse times, but there will always be a market for buying a rundown house and fixing it up to resell it.

The statistics are easy to find on the BLS website or various other government/chamber of commerce websites.

What you can do is get to the homeowner before a Realtor for a true off market sale, which is tough given that lots of Realtors pay for lists of homeowners statistically likely to sell based on this and that parameter, specifically to get in front of them.

It's 10% in the market I invest in.I would get away from being too statistical in your cash flow requirements- the investors who make the most money aren't the ones that set their criteria based on the average or median investor, per se.

You might want to look at crime statistics in the areas where you are considering investing.