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# Bias measurement

Updated on September 15, 2022

Understand how to properly measure unwanted bias in offering products to your customers to comply with your company policies and regulations.

The bias threshold measurement depends on the type of field that you selected. Depending on your settings, you can select the rate ratio or Gini coefficient.
Pega Customer Decision Hub

Rate ratio
Use this ratio to determine bias for categorical fields by comparing the number of customers who were selected for an action to those not selected for an action, and correlating that to the selected bias field. For example, the rate ratio that is represented in the following table indicates that actions are sent more often to male rather than female customers:

### Example rate ratio

 Female customers Male customers selected for the action 500 1000 not selected for the action 20000 18000 rate ratio [500 / (500+20,000) ] / [1000 /(1000+18000] = 0.46 [1000 / (1000+18,000) ] / [500 /(20,000+500] = 2.16
A rate ratio of 1 represents perfect distribution equality. You can select a warning threshold between 1 (warn if any bias is detected) and 0.50 - 2.00 (warn only if very high bias is detected). You can also choose to ignore this bias field for a particular issue in your business structure.
Gini coefficient
Use the Gini coefficient calculate bias for numerical fields. This is a method of measuring the statistical inequality of value distribution, for example, the distribution of actions to customers based on their age. A Gini coefficient of 0 represents perfect distribution equality. You can select a warning threshold between 0 (warn if any bias is detected) and 0.7 (warn only if very high bias is detected). You can also choose to ignore this bias field for a particular issue in your business structure.
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