Fannie is using this to show that appraisers have been using adjustments that are too low, resulting in less reliable values. They are often low “legacy” adjustments. Also, GLA adjustment is one of the few factors that work well in regression.
I suggest using replacement cost new less depreciation. For replacement cost you can use local builders or cost service such as Marshall & Swift, whichever is more accurate in you area. Then take off depreciation. The result is depreciated cost. Divide by GLA. The result is depreciated cost per sq.ft.
Fannie uses price divided by sq.ft. which does not consider land value or depreciation, information which Fannie does not have available.
For example, builders cost on a property is $100 per sq.ft. Your estimated physical depreciation is 30%. Obviously, $25 per sq.ft. adjustment is not correct. There may be functional or external depreciation, which you can include. Be sure to include how you determined your GLA adjustment in your appraisal.
Market based GLA adjustments are better, such as matched paired sales but the method above will work as a guideline.
Why are adjustments low? To comply with the 15/25% adjustment guideline, which Fannie has removed. It was never a requirement. Fannie has never had a 10% per line adjustment guideline. Of course lenders and AMCs can still require the use of the 15/25% adjustment which could be a big problem for appraisers which can result in less reliable values. I never considered the 15/25 guideline in any of my appraisals, but I never worked for lenders or AMCs who required that appraisals conform to it.
Check out the graphs on GLA and 15%/25% adjustments in the FAQ document below. I included 4 of them in this month’s paid Appraisal Today newsletter.
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