spb/cancerindex

1# ADR-006 — No composite score in Phase 123Status: accepted (2026-09-08)45## Context67A single "impact" or "priority" score per cancer is attractive for headlines and for the homepage,8and the specification foresees composite indexes (CI-IMPACT etc.) in a later phase (§353). Composite9scores, however, hide weighting choices, mix units and uncertainty levels, and are the values most10likely to be misread as clinical or policy verdicts. In Phase 1 the platform still lacks the burden11layer for most of the world (GLOBOCAN license review, SEER credentials), so any composite would be12dominated by whichever inputs happen to exist.1314## Decision1516Phase 1 ships **single-input, fully explained metrics only** — the catalog in17`packages/database/src/seed-data/metrics.ts` (burden counts and rates, mortality-to-incidence ratio,185-year survival, trial counts, publication counts and growth, curated evidence and gene counts,19genomic cohorts) plus two **two-input gap indexes** (`trial_gap`, `research_gap`) whose formula is a20transparent percentile difference within one scope. No weighted sum across metrics is computed,21stored or displayed. The `rankings.breakdown` column and the `composite` category in22`metric_definitions` exist in the schema but remain unused.2324## Consequences2526- Every ranking on the site answers a precise question ("which cancers have the most recruiting27  trials?"), with scope, year, source and formula version visible and "Why this rank?" available.28- The homepage cannot present a single master ordering; it presents several rankings side by side29  with their scopes, and the methodology page states explicitly that composites are not computed yet.30- When a composite is introduced (Phase 2+), it must: publish weights and components in31  `rankings.breakdown`; be versioned like any formula; be computed only where all components exist32  in the same scope (no imputation); be marked `experimental` until reviewed; and never be labelled33  as a measure of importance of a disease or a judgement on research communities (spec §324).34