Standard bias analysis examines each protected characteristic in isolation. Intersectional analysis examines combinations, such as female applicants over 55 or disabled applicants from ethnic minority backgrounds. A dataset may be adequate for each characteristic individually yet have critically small cell sizes for intersectional subgroups, making reliable bias detection impossible for those groups.
The Technical SME identifies the intersectional subgroups relevant to the system’s deployment context. The selection should be informed by the system’s intended purpose, the deployment population demographics, and any domain-specific knowledge about which intersectional groups face heightened risk. Cell sizes are reported for all examined intersectional subgroups.
Where cell sizes fall below the minimum threshold for meaningful statistical analysis (commonly 30 instances for basic metrics, 100 or more for reliable fairness metrics), the AISDP states this limitation explicitly rather than reporting unreliable metrics. Fairlearn’s MetricFrame supports intersectional analysis by accepting multiple sensitive features, computing metrics for every combination, and reporting confidence intervals. Wide confidence intervals signal insufficient data for reliable conclusions.
The practical consequence of small cell sizes is that the organisation cannot verify the model’s fairness for those subgroups through data-driven testing alone. Compensating controls include synthetic data augmentation targeted at the underrepresented intersections, enhanced post-deployment monitoring with longer observation windows to accumulate sufficient data, mandatory human review for decisions affecting individuals from intersectional subgroups with insufficient testing data, and conservative deployment restrictions. These controls are documented in the AISDP alongside the cell size analysis.
Key outputs
- Intersectional subgroup definition and cell size report
- Reliability assessment per intersectional subgroup
- Compensating controls for insufficient cell sizes