What does the Coefficient of Dispersion (COD) measure?

The Coefficient of Dispersion (COD) measures the variability of assessment ratios within a jurisdiction. This statistical tool is utilized primarily in mass appraisal to assess the uniformity of property assessments. A lower COD value indicates more uniform assessments across properties, meaning that the assessments are closely clustered around the median ratio. Conversely, a higher COD reflects greater variability, suggesting that some properties are assessed higher or lower than others in a less uniform manner.

Understanding the COD is essential for ensuring equitable property taxation, as it helps identify disparities in assessment practices that could lead to inefficiencies or inequities in the taxation system. By analyzing the variability of assessment ratios, local assessors can make informed decisions to improve assessment practices and ensure that property taxes are fair and equitable.