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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