Package index

Functions

Coefficient of Dispersion (COD)

COD is the average absolute percent deviation from the median ratio. It is a measure of horizontal equity in assessment. Horizontal equity means properties with a similar fair market value should be similarly assessed.

cod() cod_ci() cod_met()

Calculate Coefficient of Dispersion (COD)

Price-Related Differential (PRD)

PRD is the mean ratio divided by the mean ratio weighted by sale price. It is a measure of vertical equity in assessment. Vertical equity means that properties at different levels of the income distribution should be similarly assessed.

prd() prd_ci() prd_met()

Calculate Price-Related Differential (PRD)

Price-Related Bias (PRB)

PRB is an index of vertical equity that quantifies the relationship betweem ratios and assessed values as a percentage. In concrete terms, a PRB of 0.02 indicates that, on average, ratios increase by 2% whenever assessed values increase by 100 percent.

prb() prb_ci() prb_met()

Calculate Coefficient of Price-Related Bias (PRB)

(Modified) Kakwani Index (MKI)

The Kakwani Index (KI) and the Modified Kakwani Index (MKI) are Gini-based measures to test for vertical equity. They work by comparing the cumulative distribution of assessed values to the distribution of sale prices.

mki() ki() mki_met()

Calculate Kakwani and Modified Kakwani Index

Other functions

Functions for other assessment-related tasks

boot_ci()

Calculate bootstrapped confidence intervals

detect_chasing() detect_chasing_cdf() detect_chasing_dist()

Detect sales chasing in a vector of sales ratios

is_outlier() quantile_outlier() iqr_outlier()

Detect outlier values in a vector using IQR/quantile method

med_ratio_met()

Check if Sales Ratio Meets IAAO Standards

Data

Sample data used for testing and demonstrations

ratios_sample

Sample of ratio and sales data pulled from CCAO records