Just ensure the cost data sources are very clearly documented.

There are several great resources for data. 

The people who struggle here usually underestimate those factors.One thing I do differently than most: I share actual performance data from my rentals—purchase prices, rehab details, rent numbers, lessons learned, and backstories.

Plenty of comps and market data to support second/third house claim.

Criminal activity is not a protected class and actual values and opinion of values and their trajectory is just data, right?

Many people have asked & proposed to build such a data base.

I used CSV's to import data that I needed into RM.  

Beyond (formerly Beyond Pricing) – Useful for dynamic pricing and also provides some solid market data.   

This deal doesn't meet the 2% or 50% rule of thumb, but it has positive cash flow and is in a growing market, according to the latest 2024 Top 100 data from BP. 

It is only about numbers and data, and that's not a good thing.