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How Is "weight" Calculated?

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Senior Member
Oct 30, 2003
Professional Status
Certified Residential Appraiser
When Side-by-Side is chosen, the 'weight' of each comp is displayed. The 'weight' of each comp is correlated with the Gross % figure.

Do any of you know how the black box math process works whereby the lower gross % is translated into a higher 'weight?' Each comp has the same correlation.

Several appraisers use the 'weight' multiplied by the adjusted value, for each comp, and summed...to arrive at a suggested OMV. Alamode also shows that figure (rounded) at the top left under the subject header.


Apr 10, 2008
Professional Status
Certified General Appraiser
I haven't really thought too much about how TOTAL weighs sales and indicates a value. Thanks, Mr Rex for the link...good to know and I should have already made a visit to that information place.

While I look at that "value in the left-hand corner" in the side-by-side view, I explain which comparables most influence my value conclusion and rationale (e.g., similar location, most recent sale, similar tract size, walking distance to the elementary school, great walking trails for retirees, etc.). I try to explain my logic and what I decide to hang my hat on. Be smart, think smart, and write smart. I review quite a few appraisals and when I see a value conclusion such as $261,750" I know what influenced the value conclusion and it usually makes me growl. Computers are great things, but they can't see what we see (beautiful views, manicured lawns, lush pastureland, abandoned houses, moldy walls, unkept lawns) and they definitely cannot smell what we smell.


Elite Member
Aug 14, 2007
Professional Status
Certified Residential Appraiser
I've used weighted average for a long long time, the math is in book "Appraisal of Real Estate" somewhere.
I set up a spreadsheet to do it for me way back in the 1980s IIRC. I'll send you a copy of the spreadsheet
(PM me) and you can have a look at the formulas (once you find them, they're in hidden cells, as I remember)
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