Kakwani Index

assesspy.ki(assessed, sale_price)

The Kakwani Index (ki) is a GINI-based measure to test for vertical equity. It first orders properties by sale price (ascending), then calculates the Gini coefficient for sale values and assessed values (while remaining ordered by sale price). The Kakwani Index is the difference between Gini of Assessed - Gini of Sale.

For the Kakwani Index:

KI < 0 is regressive KI = 0 is vertical equity KI > 0 is progressive

Parameters:

• assessed (numeric) – A numeric vector of assessed values. Must be the same length as sale_price.

• sale_price (numeric) – A numeric vector of sale prices. Must be the same length as assessed.

Returns:

A numeric vector KI of the input vectors.

Return type:

float

Example:

# Calculate KI:
import assesspy as ap

ki(ap.ratios_sample().assessed, ap.ratios_sample().sale_price)