What Makes a Good Tenant?

[Amy E.]

I'm an engineer.  I own 5 rentals but have only been in business about 2 years.  I've had 7 tenants, 4 great, two mediocre, one lousy.  But there seems to be no trend as to what stats I could've looked for to determine if a tenant would be "good" or not.  For instance, my best tenant has the worst credit score and my mediocre tenant has the best credit score.

I'm thinking about doing a regression analysis and determining which factors really correlate to good tenants or not.  But I need some help figuring out what categories to even look at.

I'm going to start with the basics: are they employed, how much do they make, what is their credit score, have they ever been evicted, do they have a criminal background, etc.  

So, what do you all look for that means you'll get a "good" tenant.  It can be anything, even if it seems silly.