Appendix 12

Evaluating fidelity and utility of synthetic health data

Guidance for selecting and reporting evaluation measures that demonstrate how well synthetic data preserves source patterns and supports intended analysis.

Fidelity

Check how closely synthetic data matches key distributions, relationships, and rare patterns.

Utility

Confirm the dataset supports the analyses, models, or decisions required by the approved use case.

Reporting

Document chosen metrics, thresholds, and limitations for governance review and release decisions.

How to use this appendix

Before release

  • Define what "good enough" fidelity and utility mean for the approved use case.
  • Select metrics that reflect those requirements and document thresholds.
  • Report results alongside synthesis parameters and data limitations.

Pair with privacy checks

Strong utility does not guarantee safety. Combine fidelity and utility results with privacy evaluation methods from Appendix 7 before sharing data.