holisticai.bias.metrics.four_fifths

holisticai.bias.metrics.four_fifths(group_a, group_b, y_pred)

Four Fifths

This function computes the four fifths rule (ratio of success rates) between group_a and group_b. We return the minimum of the ratio taken both ways.

Interpretation

A value of 1 is desired. Values below 1 are unfair. The range (0.8,1) is considered acceptable.

Parameters

group_aarray-like

Group membership vector (binary)

group_barray-like

Group membership vector (binary)

y_predarray-like

Predictions vector (binary)

Returns

float

Four Fifths

Examples

>>> import numpy as np
>>> from holisticai.bias.metrics import four_fifths
>>> group_a = np.array([1, 1, 1, 1, 0, 0, 0, 0, 0, 0])
>>> group_b = np.array([0, 0, 0, 0, 1, 1, 1, 1, 1, 1])
>>> y_pred = np.array([1, 1, 1, 0, 1, 1, 0, 0, 0, 0])
>>> four_fifths(group_a, group_b, y_pred)
0.4444444444444444