Which statistic is helpful for measuring accuracy of appraised values by indicating the average miss from the median when considering reappraisals?

Which statistic is helpful for measuring accuracy of appraised values by indicating the average miss from the median when considering reappraisals?

• A. Coefficient of dispersion
• B. Standard deviation
• C. Mean absolute deviation
• D. Range

Answer: (A)

The statistic focused on here is about measuring how closely appraised values cluster around a central point in mass appraisal, especially after reappraisals. The coefficient of dispersion captures the average miss from the median, giving a robust sense of accuracy and uniformity. It works by looking at how far each appraisal ratio deviates from the median, averaging those absolute deviations, and expressing the result as a percentage of the median. Using the median makes this measure resistant to extreme values that often appear in appraisal data, so you get a reliable sense of typical accuracy across properties. A smaller coefficient of dispersion means reappraisals are consistently near the central value, indicating higher accuracy; a larger value signals more variability and less uniformity. Other statistics either rely on the mean, which can be distorted by outliers (standard deviation, mean absolute deviation about the mean), or only describe the extreme spread without reflecting the typical deviation (range).

The statistic focused on here is about measuring how closely appraised values cluster around a central point in mass appraisal, especially after reappraisals. The coefficient of dispersion captures the average miss from the median, giving a robust sense of accuracy and uniformity.

It works by looking at how far each appraisal ratio deviates from the median, averaging those absolute deviations, and expressing the result as a percentage of the median. Using the median makes this measure resistant to extreme values that often appear in appraisal data, so you get a reliable sense of typical accuracy across properties. A smaller coefficient of dispersion means reappraisals are consistently near the central value, indicating higher accuracy; a larger value signals more variability and less uniformity.

Other statistics either rely on the mean, which can be distorted by outliers (standard deviation, mean absolute deviation about the mean), or only describe the extreme spread without reflecting the typical deviation (range).