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ADR 0016: Equity Academic Rigor Hardening (Ontario)

Status

Accepted (2026-02-18)

Context

ADR-0015 replaced placeholder equity linkage with real Ontario census tract inputs, but an academic audit identified remaining validity and interpretation risks:

  • Quintile calibration scope could be influenced by non-ON rows.
  • API/UI messaging did not consistently prevent causal overinterpretation.
  • Equity linkage outputs lacked uncertainty/sensitivity context.
  • Reproducibility and geospatial dependency setup needed clearer controls.
  • ON layer payload size created performance risk for map loading.

Decision

For Ontario equity analytics and map serving:

  1. Calibrate income quintiles using Ontario boundary-matched tract records only (quintile_scope=ON_BOUNDARY_MATCHED).
  2. Preserve suppression provenance in processed outputs (short_income_suppressed, long_income_suppressed) and manifest missing-income breakdowns.
  3. Extend equity summary analytics with:
  4. fixed-threshold sensitivity outputs (10/20/30/40km + requested threshold),
  5. bootstrap percentile uncertainty intervals (95% CI) for descriptive metrics.
  6. Enforce explicit interpretation limits in API/UI:
  7. descriptive/associational only,
  8. no causal inference,
  9. temporal mismatch warning (Census 2021 income vs recent wait aggregates).
  10. Harden reproducibility with explicit dependency groups (dev, equity) and documented setup (uv sync --extra dev --extra equity) using pyogrio path.
  11. Generate dual layer artifacts:
  12. canonical output,
  13. optimized geometry output, with frontend/API preference for optimized and fallback to canonical.

Rationale

  • Reduces bias risk in quintile assignment by constraining scope to study geography.
  • Improves interpretive safety for users and reviewers.
  • Improves statistical transparency without implying causal claims.
  • Makes local processing repeatable on developer workstations.
  • Reduces map payload risk while preserving canonical artifact lineage.

Consequences

Positive

  • Stronger methodological defensibility for ON equity outputs.
  • Better transparency for suppressed/missing tract income data.
  • Better map performance posture through optimized geometry serving.
  • Explicit, repeated non-causal framing across API and UI surfaces.

Tradeoffs

  • Additional output/metadata complexity in APIs and manifests.
  • Bootstrap intervals are descriptive and may be unstable with very small samples.
  • Canonical+optimized artifact management adds minor maintenance overhead.

Follow-Up

  1. Apply the same hardening template when onboarding QC/AB/BC equity layers.
  2. Reassess vector-tile migration if multi-province payloads exceed acceptable API/map latency.