The school districts don't rate statistically with the best of Ohio (although Rocky River is ranked very high and just minutes away if that's what you're aiming for) but they're still great.

Statistically, almost never.

Here is the link to the NCREC statistics on "approved" schools and their pass/fail rate.  

But it's a bit of a stretch to then try to hold him to blanket-agree with the rest of your sentence: "how much you pay relative to ....the long term trends of market pricing" - which I would view as a different metric altogether, and may have little if anything to do with ongoing rent returns vs CURRENT purchase/market price.Sure, Dave will watch the look of his investment neighborhoods - but statistics are fickle! 

Firearm discharge, statistically, is higher in towns with a higher military concentration.

You will find a lot of people who have researched the Indianapolis market to death and can give you ALL SORTS of statistics..My one(or two+) words of caution is to do your due dilligence..

Is there anywhere that has statistics on average rental price and vacancy rates by neighborhood in Portland metro area?

I would love to know the statistical likelihood of these things as well.

Worst case you'll want to have whatever you're into the thing paid off by them in 10 months or less (thats the rule of thumb i've heard, not sure if its based on statistics of people trashing the things and running off) , 6 months is better and of course up front is best.So if you got the thing for 2k and they pay you 200 a month for it that works great (sell it to them for say...5k) , but you'll run into trouble if it takes longer than 10 months to get your money back out of the deal (again, just the rule of thumb i've always heard)

The other caution on Trulia- The crime statistics change over time.