What is the formula to determine the Coefficient of Dispersion (COD)?

The Coefficient of Dispersion (COD) is a statistical measure used in appraisal to assess the level of uniformity of property assessments. It measures the variability of assessment ratios relative to the average ratio. The correct formula for COD is the Mean Deviation divided by the Median Ratio.

Using the Mean Deviation provides insight into how much individual assessment ratios differ from the median of those ratios. The median is particularly appropriate in this context because it is less affected by outliers in the data than the mean, thereby providing a more representative central tendency for the distribution of ratios. By dividing the Mean Deviation by the Median Ratio, the result gives a sense of the dispersion of the data in relation to a central point, aiding in determining the fairness and consistency of assessments across properties.

The other options presented do not align with the established formula for COD, making the choice of Mean Deviation/Median Ratio not only correct but essential for accurate appraisal analysis.