validation: bind Rubin factor-score design payload into projection authority #522

Finding

Current Draft #506 binds the exact cutoff-admitted complete-data indicator draw matrix through complete_data_draws_sha256, but the Rubin loading estimator also consumes the cutoff-admitted factor_scores vector. EligibleRubinRows::complete_data_draws_sha256() hashes dimensions and draw values only; it does not hash factor_scores.

That leaves a real provenance gap for any future positive projection: with the same snapshot/cutoff, indicator draws, observation/draw counts, indicator kind, and approved class-level pairing, changing the already-mapped factor-score vector can change the OLS loading estimates while preserving the activation receipt's concrete draw digest. source_snapshot_sha256 does not close this by itself because the executor accepts already-mapped factor scores as caller-supplied numeric inputs and does not prove that mapping from source bytes.

Required contract

• the executor must bind every cutoff-admitted numeric input that enters psychometric_core::recover_loading_point_estimate_mean / combine_draw_level_ols_loadings, including the factor-score design vector;
• a late row excluded by AvailableTime > KnowledgeCutoff must not change that commitment;
• a one-bit change in an admitted factor score must change the commitment;
• the public activation receipt/runtime decision must not be able to authorize a factor-score-substituted run merely because the indicator draw matrix digest is unchanged;
• keep generator-execution attestation separate: content commitment is still not proof that an approved generator or mapping implementation produced the bytes;
• production approved pairing remains empty until independent scientific promotion.

Prefer a versioned executor-owned numeric-analysis-payload commitment or an explicit factor-score commitment rather than silently overloading the meaning of a field named complete_data_draws_sha256. The receipt/artifact schemas are still Draft and unreleased, so the eventual v1 can be corrected before protected-main publication.

Evidence

At #506 exact head a40dab07044c6d77ebe3514ee9ef215dc09970d7, EligibleRubinRows contains both factor_scores and indicator_draws, but complete_data_draws_sha256() hashes only the latter. The executor then passes both vectors into the loading point estimate and Rubin combination.