What statistical measure would you need to calculate when using COD?

When using the Coefficient of Dispersion (COD), the median is the critical statistical measure to use. The COD is a measure of the uniformity of assessment ratios in mass appraisal, and it specifically compares the average assessment ratio to the median assessment ratio across a set of properties. This focus on the median is significant because it is less affected by extreme values or outliers compared to the mean. In practice, the median provides a better indication of central tendency in skewed data distributions, which are common in real estate and property assessments.

The COD formula incorporates the median to assess how assessment ratios deviate from this midpoint, thus helping to understand the consistency and accuracy of property valuations in relation to a benchmark. Therefore, calculating the median is essential for determining the COD accurately.