What is your data source concerning under 1000 doors investors?

Trying to get an appraiser from the area to drive out to a property (based on data from a LONG time ago) for a "competitive price" is a miserable experience!

I would take the city at their word on the water historical data.

It will vary from market to market, but most markets have a variety of public data available.

I like to be informed of the long run of the market before jumping in, and I hope to bring that philosophy into real estate.How granular can the data get, say for the metropolitan area level, for metrics such as inflation-adjusted rent (for 1 br?

They use various algorithms and public data which vary wildly.

You need data showing the difference on relatively large sample say N=10 per sf.You may make tenants happier that someone is not ripping other off.

What is the most efficient way to get this data?

It's still quite affordable for multifamily investors, the commute is easy, and the area has been appreciating over time, besides being very family-oriented.I'm a data-driven kind of broker, and I find this graphic from Bloomberg to be extremely helpful: https://www.bloomberg.com/graphics/property-prices...Also, make sure to always check NYC's crime map: https://maps.nyc.gov/crime/ You can also see crime rates on Trulia and will soon realize that many listings for sale are on "hot spots" on those maps, so be mindful of that.I would also strongly advise you to find a good broker in order to assist you in the transaction: it may give you a clear advantage over other investors as they will know how to put you in the best position when presenting an offer and may be also aware of off-market deals. 

The actuary uses claim data to determine risk.