Be careful with the free data sites, they really rely on algorithm which can pull some funny numbers. 

The prognostications of developers and AI people  are so tightly constrained by their beliefs that an algorithm will solve everything.

I guess their algorithm needs a tuneup. 

Quote from @Agustin Rossi: It's an algorithm based valuation based on internal data. 

Because I have experienced algorithm changes over the years that were completely unexplainable, where properties that have been high in the rankings all of the sudden stop booking with no viable explanation.  

Account Closed, the biggest issue with AirDNA is the algorithm.

I agree with @John Underwood and @Bruce Woodruff.Like any algorithm, the more data points, the more accurate the data will be.

FHA loans are underwritten by an algorithm unless they turn into a manual underwrite.

This data set would be a metric representation of the market direction and strength of that direction, be it growth, decline, appreciation, depreciation.I created my own algorithm for calculating such data and disseminating it into a charitable data representation, but that is just me and my own understanding of how I feel things should be weighed and measured.

So I went through a spell maybe 18 months ago, where several of my top producing 5 star cabins just stop booking, and never could figure out why other than perhaps an algorithm change.