Regresses the cross-section of returns onto a 7-factor model (value, momentum, size, quality, low-vol, …) and reports which factor explains the most dispersion this quarter, plus the model's overall fit.
A reading of "momentum, R² 0.62" says momentum was the dominant axis of return dispersion this quarter and the factor model captured 62% of it. High R² = a factor-driven tape; low R² = idiosyncratic.
The side split-bar in the Returns chapter ("Which factor explains the cross-section?"); CONTEXT factor-decomposition voice.
Graded on the Tier-1 regime-test harness — curated macro events × 18-yr backfill × recall@K. Verdict WARN (R² 0.77 EFA OOS).