Back to Search-quality baseline: acronym / synonym recall (Phase 1.4, v1.2.0 candidate)

Metric | Value
--- | ---
Synonyms tested | 22
Canonical framework at top-1 | 4 / 22 (18.2%)
Canonical in top-5 | 11 / 22
Canonical in top-10 | 13 / 22
Canonical missing from top-10 | 9 / 22
MRR | 0.2562

Binomial test (top-1 == canonical vs chance 0.5): k = 4 of n = 22, one-sided p = 0.9996. The null hypothesis (synonyms-mechanism has no effect beyond chance) is not rejected; if anything, the data is consistent with the synonyms-mechanism actively producing worse results than random for top-1 retrieval.

Compare to the other class baselines on the same DB:

Class | Top-1 hit rate
--- | ---
A canonical lookup (`search-quality-baseline`) | 46/50 (92%)
E deprecation-aware (`search-quality-deprecation`) | 30/30 (100%)
F cross-source canonical (`search-quality-crosssource`) | 19/19 conditional (100%)
D CamelCase fragment (`search-quality-fragment`) | 20/20 (100%) at any-match
C acronym / synonym (this doc) | 4/22 (18%)

This is the worst-performing class baseline by a wide margin.