1. What is the Four Fifths Rule?

The Four-Fifths Rule (or 80% rule) is a guideline for determining adverse impact in employment decisions. It compares selection rates between protected groups and majority groups to identify potential discrimination.

2. How Does the Calculator Work?

The calculator uses the Four Fifths Rule formula:

Where:

• \( IR \) — Impact Ratio (decimal)
• \( \text{Minority Rate} \) — Selection rate for protected group (0-1)
• \( \text{Majority Rate} \) — Selection rate for majority group (0-1)

Interpretation: An impact ratio below 0.8 (four-fifths) suggests potential adverse impact that may warrant further investigation.

3. Importance of Impact Ratio

Details: The Four-Fifths Rule is widely used in employment law and HR analytics to screen for potential discrimination in hiring, promotions, or other employment decisions.

4. Using the Calculator

Tips: Enter selection rates as decimals between 0-1 (e.g., 0.25 for 25%). The majority rate cannot be zero. The calculator will show whether the result passes or fails the four-fifths rule.

5. Frequently Asked Questions (FAQ)

Q1: Is the Four-Fifths Rule a legal standard?
A: It's a rule of thumb used by the EEOC, but courts may consider other factors in discrimination cases.

Q2: What if my IR is exactly 0.8?
A: This is the threshold - exactly 0.8 technically passes, but borderline cases may warrant review.

Q3: Can I use percentages instead of decimals?
A: Yes, just divide your percentages by 100 before entering (e.g., 25% → 0.25).

Q4: What sample size is needed for reliable results?
A: Small samples may produce unreliable IRs. Statistical significance tests are recommended for small groups.

Q5: Does passing the rule guarantee no discrimination?
A: No, it only screens for adverse impact. Other evidence might still show discrimination exists.