What is accross the board adjustment in real estate?

“Across-the Board-Adjustments” are applied to real estate
appraisals.  Adjustments are made when the subject property is compared to comparable
properties.  Adjustments are in either of two directions, CIA = comparable inferior,
value is added to subject property, CBS = comparable superior, value is subtracted from
subject property.

The ideal appraisal involves actual and
specific evaluation by the appraiser of the subject property and the comparables. 
Adjustments are then based on real and specific differences in the properties such as
property location, condition, curb appeal, lot size and so
forth.

Across-the-board adjustments are based on a general
concept of the differences between the subject property and comparables, and are not
necessarily supported by reality.  Since specific evaluations are not employed, there is
a chance of inaccuracies in either direction (CIA or
CBS).

The reference gives tips on evaluating a real estate
appraisal.  It outlines the danger of across-the-board adjustments.  It instructs how to
examine the appraisal critically in order to detect the likely accuracy (or lack
thereof) of the appraisal.