Time adjustments have long been required as good appraisal practice.  On the residential side, they are required in guidelines issued by FannieMae and FreddieMac (the GSEs).

Unfortunately, the requirement for time adjustments (“market conditions”) has been ignored by the lenders selling to the GSEs (Government Sponsored Enterprises).  Why?

Editor’s Note: Read Part 1 of this series here.

Here we seem to have a case of a fundamental fallacy:  the fallacy of insufficient reason — It’s too hard, so let’s avoid it.  Worse yet, this bias-causing fallacy is embedded in bureaucratic policy, and by extension, failure of enforcement by the GSEs and several agencies.  We go from group-think, to org-think, to ignored-rule-think.  I think.

All this in the face of an appraisal standard where USPAP requires analysis of supply and demand, and market area trends.  Any conclusion that the market is going up, down, or level – requires “support.”  An “unsupported assumption or premise about market area trends” must be avoided!  (Rule 1-3(a))

In a recent paper written by Scott Susin, FHFA senior economist, the research shows that:

  • Appraisers tend to do time adjustments last (as a fudge factor?)
  • If the appraised value is “high enough”, time adjustment tends to be “zero” (null)
  • Any “underappraisal” amount is covered some ¾ of the time, to help make the value “come in.”

Blog | Federal Housing Finance Agency Underappraisal Disparities and Time Adjustments (fhfa.gov)

Dr. Susin’s research also showed an unexpected “bias” result:  there is a disparity in the occurrence of time adjustments in majority-black tracts versus majority-white tracts.  When focused on “underappraisals,” the disparity becomes greater.

It appears that the unsystematic and uninforced use of time adjustments can make appraisals less reliable, and potentially analytically biased.  In any case, the unenforced guidelines, ignored appraisal standards, and scofflawed requirements by the GSEs and their client lender banks – creates yet another opening for appraisers to be accused of personal bias (whether true or false).

Is it time to make time for time adjustments?  It appears so.

My initial view on what might be important:

  1. It must be a required result-field.
  2. Zero (absolutely level) trend is not a way to cop out. Zero is not the same as “Ida no.”
  3. It must reflect the actual CMS© (Competitive Market Segment), not something else.
  4. The method used should be consistent, and reproducible by a reviewer or auditor

Any new solution must follow the best practices of econometrics, and of time-series analysis.  My prior journal articles in The Appraisal Journal (Appraisal Institute), reflect some of these best practices.  It is my hope that this issue is addressed square on, not relying (again) on uneducated “common sense.”  Some statistical methods simply are not intuitive.  It is easy for those with no real knowledge in econometrics and time-series regression – to make obvious mistakes.

This happened once before with the infamous 1004mc GSE form.  It is my belief that that form grossly violated good analytic practice, and imposed it on the profession, the lenders, and our regulators – to the detriment of the public trust.

We have the right solution.  We need to require it, every time, every appraisal.

WE MEASURE MARKETS, NOT COMPARE COMPS.