Meaning
Numerical calculation used to compare the success rates of different demographic groups in a selection process. A disparate impact ratio is calculated by dividing the selection rate of a protected group by the selection rate of the most favoured group. It identifies potential bias even when no discriminatory intent exists in the underlying algorithm.
Courts and regulatory bodies use this figure to determine if a practice disproportionately excludes certain populations.
Legal Benchmark
Distribution contracts for software often cite specific ratios that must be maintained to avoid litigation. A value below 0.8 is commonly regarded as evidence of adverse impact in employment contexts. This benchmark allows organizations to quantify their legal exposure before a product enters a new market.
Selection Equity
The metric forces a comparison between raw outcomes rather than internal model logic. It provides a simple way to verify if a procurement process remains fair. Vendors who fail to meet the required ratio may be barred from government contracts.
Quantitative Risk
Managing this ratio involves regular auditing of live decision data. The calculations must be updated as new populations interact with the system. Because the metric is sensitive to small sample sizes, its application requires careful statistical oversight.
It provides a clear indicator of systemic exclusion.
