They survey realtors and other RE industry pros and compile lots of data.

It's up to the investor to figure out which data to act on.A couple things taken from the most recent NAA operating income and expense survey (the subject market is in Region IX). 

I imagine with a soil survey and a properly engineered foundation it should be possible to build.

I recently read and responded to a post initiated by @Adam Zach surveying all members wanting to see who in the real estate investing world came from an engineering background.  

I am kind of a data hound, so...wanted to share some of my conclusions from the American Housing Survey of 1995/6: [comments are mine from a paper written on the subject, not from the study directly]"On average, renters move out most commonly due to factors not influenced by the owner/landlord such as a new job, job transfer, to shorten the commute, to purchase their own home, or to move into a larger unit.

If you do need a variance and/or special permit, you'll need to provide a survey too. 

@Jonathan Greene I bought a house without getting a survey.

Do you go through their educational videos, or any specific surveys / tables you find that it is helpful.Sorry --- try to do some shortcut on that massive website. 

Its these kind of survey's that the investors or promoters hang there hat on and its not reality in the real world Kind of like Zillow is for values  :)

Right now I am generating buyer leads for as low as $4 and am able to close 40% of those because they are super qualified through a short survey I run.