Document Date
Meeting Description
Document Type
Meeting Date
Page Number
27
Measurements of Equity
Coefficient of Dispersion (COD)
Measures the uniformity of assessments by measuring
the average percentage deviation from the median ratio.
The lower the COD, the more uniform the ratios within
the property group.
Price-Related Differential (PRD)
Tests for appraisal equity between lower and higher
value properties or price-related bias. A PRD below 1.00
tend to indicate assessment progressivity, the condition
which assessment ratios increase with price. A PRD
above 1.00 tends to indicate regressivity, in which
assessment ratios decline with price. The PRD is
calculated by dividing the mean ratio by the weighted
mean.
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