Check for spikes in tenancy, and significant deviations in regular expenses.Kenneth and Andrew made good comments.

I haven't been able to find any evidence of property values spiking (or even increasing at a higher rate) since that Cerner campus was completed.  

If the area has constant population / labor outflow, the prices would naturally depreciate, on the contrary more desirable areas with better economics and new employment opportunities naturally spike realty value growth. ( however important to look into diversification of major employers not to get into Detroit situation)I would look into state first with good economic growth, then dig into counties and narrow down to town profiles ( unemployment rate, poverty rate, schooling, budget proficit / deficit )Prices approaching 2007-2008 marks in certain areas may indicate soon-to-come market correction, so comparing those years data to current may give some insight as well.Good luck!

Rates spike and the note readjusts during your hold period. 

Also prices have spiked in Jan and I’ve noticed properties that have been listed awhile that aren’t pending are now raising their prices!  

Your only play is appreciation due to a crop price spike like 10 to 15 years ago.

This is great when it happens because your yield to maturity really spikes, because whatever discount you purchased the loan at is being caputred a lot faster than if they just paid the normal P&I every month.  

I have heard they can be very expensive to run and would spike the power bill a good bit. 

I thought Id check Zillows mortgage rate tracker to confirm...and sure enough mortgage rates have spiked considerable.

Note how the low data point for this was in 2005 at 18 DOM, and a sharp spike in 2008 up to 58 DOM.