Methods
Small Details In Evaluation
Beyond high-level design, small technical choices can materially change program evaluation findings. This guide summarizes details to watch when evaluating Model A or similar healthcare programs.
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1. Data nuances and coding discrepancies
- Normalize variable definitions across systems so eligibility logic is consistent.
- Document coding exceptions (for example, assistive-device logic) before final cohort lock.
- Maintain an up-to-date participating clinician ID file to avoid treatment-group leakage.
2. Participant switching and behavior
- Track crossover: treatment-to-usual-care and usual-care-to-similar-service movement.
- Choose estimand up front: intent-to-treat vs. re-eligibility-based follow-up.
- Quantify dilution risk when switching rates are high.
3. Outliers and site-level influence
- Run leave-one-site-out sensitivity tests to assess concentration risk.
- Handle extreme-cost outliers with a prespecified rule (for example, 99th percentile trimming/winsorizing).
- Report both trimmed and untrimmed estimates for transparency.
4. Unmeasured environmental factors
- Care setting differences (home vs. congregate setting) can shift observed ED/hospital use.
- Family and caregiver capacity can materially affect acute utilization independent of program quality.
- Capture these risks in limitations and, when feasible, stratified analyses.
5. Interaction with other programs
- Check overlap with ACOs and other concurrent initiatives targeting the same population.
- Flag shared-attribution risk in interpretation of savings and utilization changes.
6. Baseline rigor checks
- Verify pre-trends over at least two years, not just one baseline year.
- Evaluate geographic expansion effects that may change cohort case-mix year over year.
- Re-run results on stable-coverage subcohorts as a robustness check.
Related methods
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