{ "experiment": "SRP-RIGIDITY-01", "james_message": "996d837f-0c33-4d66-9d14-849cef60e1e2", "locked_at": "2026-09-10T19:10:00Z", "support_rule": { "joint_share_ge_0_5_plus_six_sign": "WITHDRAWN_AS_CONFIRMATORY", "retained_in_history": true, "descriptive_label": "SUPPORTED_DESCRIPTIVELY", "scope": "HOUSE_ENDPOINT_TREND_ONLY", "senate": "MIXED", "general_elite_rigidity": "NOT_ESTABLISHED" }, "measurement_families": { "nominate_geometry": [ "N1", "N3" ], "brookings_party_unity": [ "N2" ], "independent_family_count_claim": "INDEPENDENT_FAMILY_COUNT_NOT_ESTABLISHED", "operationalizations_preserved": { "nominate_geometry": [ "N1", "N3" ], "brookings_party_unity": [ "N2" ], "note": "Distinct operationalizations/source-lineage retained; count of independent families is NOT established under shared-upstream correction." }, "prior_claim_on_v1": "TWO_LINES_NOT_THREE", "prior_claim_status": "SUPERSEDED_NOT_ERASED" }, "alternatives": [ { "id": "A", "name": "NOMINATE scaling/career-score artifact", "disposition": "PLAUSIBLE", "discriminating_test": "Do NOT mix measurement change with cohort change in one contrast. Run two separate design-only sensitivities against career NOMINATE baseline (Cong 100–117 House N1/N3): (A1) session-only scores for the same members; (A2) freshman-only cohort subset with career scores held constant. Report each vs baseline separately; do not pool into one test.", "sensitivities": [ { "id": "A1_session_only", "changes": "measurement_definition_only", "cohort": "same_as_baseline", "contrast": "session-only NOMINATE vs career NOMINATE on identical member set", "prediction_if_A_true": "House endpoint/trend signal attenuates or flips under session-only scores while member set unchanged", "confounding_limits": "Session scores still inherit roll-call agenda; not a pure scaling fix", "sources_needed": [ "Voteview session NOMINATE", "Voteview career NOMINATE", "member crosswalk" ], "scope": "DESIGN_ONLY; no execution authorized here" }, { "id": "A2_freshman_only", "changes": "cohort_only", "measurement": "career_NOMINATE_unchanged", "contrast": "freshman-only cohort vs full career baseline on same score definition", "prediction_if_A_true": "Signal concentrated in career-long members; freshman-only weakens consolidation pattern", "confounding_limits": "Freshman composition also tracks realignment/sorting (overlaps B); cannot alone prove scaling artifact", "sources_needed": [ "Voteview career NOMINATE", "member first-Congress flags" ], "scope": "DESIGN_ONLY; no execution authorized here" } ], "prior_v1_test_problem": "Mixed session-only with freshman-only in one line (measurement AND cohort)." }, { "id": "B", "name": "Party sorting/realignment composition change", "disposition": "PLAUSIBLE", "discriminating_test": "Recompute N1 after party-affiliation-change adjustment (Southern realignment)", "scope": "DESIGN_ONLY; no execution authorized here" }, { "id": "C", "name": "Roll-call agenda selection", "disposition": "PLAUSIBLE", "discriminating_test": "Fixed vote-type subsample; procedural vs substantive split", "scope": "DESIGN_ONLY; no execution authorized here" }, { "id": "D", "name": "Chamber rules/institutional differences", "disposition": "PLAUSIBLE", "discriminating_test": "Within Senate (and mirrored House control), compare NOMINATE N1 trend on procedural/calendar votes vs substantive roll-calls after matching career scores. Competing prediction: if chamber rules/institutions drive House−Senate asymmetry, the procedural subsample shows a larger chamber gap than the substantive subsample; if NOMINATE scaling (A) or sorting (B) dominate, gaps look similar across vote types. Sources: Voteview roll-call codes + chamber calendars/procedural flags, Cong 100–117. Scope: design-only contrast plan — not the Senate contrary N1 descriptive fact restated as a test. RIGIDITY-02 remains NOT_AUTHORIZED.", "comparison": "procedural_vs_substantive within chamber, then House−Senate gap size by vote class", "prediction_under_D": "procedural gap > substantive gap", "prediction_under_A_or_B": "similar gaps across vote classes after score/cohort controls", "sources_needed": [ "Voteview", "procedural/substantive vote classification", "chamber calendars" ], "scope": "DESIGN_ONLY; RIGIDITY02_NOT_AUTHORIZED", "prior_v1_test_problem": "Restated Senate contrary N1 descriptive evidence rather than a discriminating institutional test." }, { "id": "E", "name": "Shared roll-call provenance / Brookings continuity", "disposition": "PLAUSIBLE", "discriminating_test": "Map 8-4 vintage/normalization lineage by year; keep frozen hashes; no splice", "scope": "DESIGN_ONLY; no execution authorized here" }, { "id": "F", "name": "Two-party sorting without broader system rigidity", "disposition": "PLAUSIBLE", "discriminating_test": "Compare elite NOMINATE polarization trajectory (House N1/N3, Cong 100–117) to mass partisan affect/sorting on ANES (and GSS if overlapping years) feeling-thermometer / party-ID folding over the same Congress windows. Competing prediction: if F true, elite consolidation continues while mass sorting stays flat or weaker on the same windows; if general system rigidity, mass and elite move together. Observable contrast is elite-vs-mass co-movement, not a vague out-of-scope domain label. Sources: Voteview + ANES/GSS public files. Scope: descriptive co-movement design only; no outcome/electoral tests; do not escalate into RIGIDITY-02.", "comparison": "elite_NOMINATE_trajectory vs mass_ANES_GSS_partisan_sorting same windows", "prediction_under_F": "elite consolidates; mass flat/weaker", "prediction_under_general_rigidity": "elite and mass co-move", "sources_needed": [ "Voteview", "ANES", "GSS (optional overlap)" ], "scope": "DESIGN_ONLY; descriptive co-movement; no outcome tests", "prior_v1_test_problem": "Named a broad research domain without an observable contrast." } ], "rigidity_02_execution": "NOT_AUTHORIZED", "theory_exposure": "INDEPENDENT_BUT_THEORY_EXPOSED_REVIEW", "refs": { "claude_adjudication": "39ca9ed4", "astra_provenance": "cbf82874 / astra:bc41c8a0", "astra_synthesis_relay": "14d6c891", "brookings_audit": "41ae1339", "codex_af_review": "32437088-3816-4d0d-9695-52a1d0f15da0", "astra_af_gate": "0220a4e7-8e97-4664-a304-420ba157f474", "v1_locked_sha256": "ac7c1a1dd237952783e2e38f2167187f26822c748665192d0b2a6e8363de984c" }, "artifact_version": "v1.1", "supersedes": { "path": "/docs/srp-rigidity-01-alternatives-af.json", "alias_locked_copy": "/docs/srp-rigidity-01-alternatives-af-v1-locked.json", "sha256": "ac7c1a1dd237952783e2e38f2167187f26822c748665192d0b2a6e8363de984c", "locked_at": "2026-09-10T19:10:00Z", "reason": "Codex 32437088 + Astra a9173947: independent_family_count_claim contradicted shared-upstream correction; D/F tests not discriminating; A mixed session-only with freshman-only cohort change." }, "correction_at": "2026-09-10T19:30:09Z", "authorship": { "author_agent": "grok", "author_role": "builder", "reviewer_required": "claude", "adjudication_refs": { "codex_review_comment": "32437088-3816-4d0d-9695-52a1d0f15da0", "astra_gate_comment": "0220a4e7-8e97-4664-a304-420ba157f474", "astra_decision_id": "astra:a9173947-2e1c-4b56-b365-f9a210a52ad6" }, "exposure_status": "BUILDER_CORRECTION_PUBLIC; NOT_INDEPENDENT_REVIEW_ACCEPTANCE", "note": "Grok builder lock/correction ≠ Claude independent acceptance. Gate remains OPEN." }, "execution_status": { "rigidity_01_recompute": "NOT_AUTHORIZED_BY_THIS_CORRECTION", "rigidity_02": "NOT_AUTHORIZED", "empirical_tests_in_this_artifact": false, "numerical_thresholds": false } }