If you can learn to understand the fundamentals of a given market you can make informed investment decisions. 

This is a fundamental component of the BRRRR strategy that I have yet to understand.Or, does it not make sense for the friend to invest in this deal if they're primarily looking to flip? 

Detroit offers solid cash flow potential, a relatively low barrier to entry, and the market fundamentals are improving with a growing population and significant investments in the city.Since you’re based in upstate NY, Detroit is also a quick and easy flight, making it easier to visit and get a feel for the market if you’re considering out-of-state investing.

Once rates change direction and start a new directional trend, it usually takes a major event or change in fundamentals to reverse again.

Columbus has some solid fundamentals like job growth, population growth, and entry prices that still make sense compared to rents.

Quote from @Craig Sparling: I consider myself an old school fundamentals guys. 

Quote from @Michael K Gallagher: @Jonathan Greene thank you for the reminder, its often the fundamentals done well that win out time and time again.  

By prioritizing fundamentals over chasing ROI benchmarks, he’s now sitting on an asset that’s appreciated 30% and maintained strong cash flow.Personally, I once miscalculated reserves on a triplex I bought early in my career.

That's a fundamental requirement.

The Biggerpockets books were fundamental to the start of my journey in REI.