Enter the number of unfavorable outcomes for both the protected and non-protected groups, and their total numbers into the calculator to determine the Disparate Impact Ratio.

## Disparate Impact Formula

The following formula is used to calculate the Disparate Impact Ratio (DIR).

DIR = (a / A) / (b / B)

Variables:

• DIR is the Disparate Impact Ratio
• a is the number of unfavorable outcomes for the protected group
• A is the total number of the protected group
• b is the number of unfavorable outcomes for the non-protected group
• B is the total number of the non-protected group

To calculate the Disparate Impact Ratio, divide the number of unfavorable outcomes for the protected group by the total number of the protected group. Then, divide the number of unfavorable outcomes for the non-protected group by the total number of the non-protected group. Finally, divide the first result by the second result. If the DIR is less than 0.8, it may indicate a potential disparate impact, which could be a sign of discrimination, even if unintentional.

## What is a Disparate Impact?

Disparate Impact refers to a policy, practice, rule or procedure that appears neutral on its surface, but has a discriminatory effect or impact on a protected group when implemented. It is a legal theory under the Civil Rights Act in the United States, primarily used in employment discrimination cases, where a plaintiff can claim discrimination even if the employer did not intend to discriminate. The focus is on the outcomes of the policy or practice rather than the intent behind it.

## How to Calculate Disparate Impact?

The following steps outline how to calculate the Disparate Impact Ratio (DIR).

1. First, determine the number of unfavorable outcomes for the protected group (a).
2. Next, determine the total number of the protected group (A).
3. Next, determine the number of unfavorable outcomes for the non-protected group (b).
4. Finally, determine the total number of the non-protected group (B).
5. After gathering the necessary variables, use the formula DIR = (a / A) / (b / B) to calculate the Disparate Impact Ratio.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Number of unfavorable outcomes for the protected group (a) = 20

Total number of the protected group (A) = 100

Number of unfavorable outcomes for the non-protected group (b) = 30

Total number of the non-protected group (B) = 200