{"abstract":"Global treatment overlap conceals an unsupported target stratum.","category":"Causal analysis data contracts","checks":6,"contract":"Rows [stratum,arm] encode observed design support. Return target strata lacking either arm, sorted. Multiplicity is irrelevant.","contract_signature":"rows, target","evaluation_group":"model-3cf24d01381b0e2a","failed_approach":"Checking only observed strata forgets target strata absent from the study.","family":"z-causal_inference-stratum-support","id":"FA-12656","implementations":{"attempt":{"sha256":"ebe187a1a9e7f170dfc67a52dc0194a48e5dd51d035dd2541861e8965d5885e1","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows, target):\n    observed = {r[0] for r in rows}\n    return sorted(s for s in target if s in observed and {a for t,a in rows if t == s} != {0,1})\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('separated arms', solve([['a',0],['b',1]], ['a','b']), ['a','b'])\ncheck('absent target', solve([['a',0],['a',1]], ['a','b']), ['b'])\ncheck('supported', solve([['a',0],['a',1]], ['a']), [])\ncheck('empty target', solve([['a',0]], []), [])\ncheck('empty study', solve([], ['a']), ['a'])\ncheck('duplicate rows', solve([['a',0]]*N, ['a']), ['a'])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"a7c2d64d48f1fea989a09c6c1cd344735f3384553a361f44769a028996570fc9","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows, target):\n    return [] if {r[1] for r in rows} == {0,1} else sorted(target)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('separated arms', solve([['a',0],['b',1]], ['a','b']), ['a','b'])\ncheck('absent target', solve([['a',0],['a',1]], ['a','b']), ['b'])\ncheck('supported', solve([['a',0],['a',1]], ['a']), [])\ncheck('empty target', solve([['a',0]], []), [])\ncheck('empty study', solve([], ['a']), ['a'])\ncheck('duplicate rows', solve([['a',0]]*N, ['a']), ['a'])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"Finite, fully specified synthetic data only; identification assumptions are supplied by the fixture design, not inferred from observations. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"z-causal_inference-stratum-support","generated_at":"2026-09-29T14:38:58.794348+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic synthetic study model isolates this data-contract defect; outputs alone establish no real-world causal identification.","root_cause":"Presence of both arms globally is mistaken for conditional design support.","sha256":"70a6a6ec5ed4119e36832b40828b7ca0d032426fe8eeb954f9c8c32e1170e6d2","title":"Global treatment overlap conceals an unsupported target stratum · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":40.045,"exit_code":1,"observations":[{"actual":["a","b"],"check":"separated arms","expected":["a","b"],"passed":true},{"actual":[],"check":"absent target","expected":["b"],"passed":false},{"actual":[],"check":"supported","expected":[],"passed":true},{"actual":[],"check":"empty target","expected":[],"passed":true},{"actual":[],"check":"empty study","expected":["a"],"passed":false},{"actual":["a"],"check":"duplicate rows","expected":["a"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"separated arms\", \"actual\": [\"a\", \"b\"], \"expected\": [\"a\", \"b\"], \"passed\": true}, {\"check\": \"absent target\", \"actual\": [], \"expected\": [\"b\"], \"passed\": false}, {\"check\": \"supported\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty target\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty study\", \"actual\": [], \"expected\": [\"a\"], \"passed\": false}, {\"check\": \"duplicate rows\", \"actual\": [\"a\"], \"expected\": [\"a\"], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.645,"exit_code":1,"observations":[{"actual":[],"check":"separated arms","expected":["a","b"],"passed":false},{"actual":[],"check":"absent target","expected":["b"],"passed":false},{"actual":[],"check":"supported","expected":[],"passed":true},{"actual":[],"check":"empty target","expected":[],"passed":true},{"actual":["a"],"check":"empty study","expected":["a"],"passed":true},{"actual":["a"],"check":"duplicate rows","expected":["a"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"separated arms\", \"actual\": [], \"expected\": [\"a\", \"b\"], \"passed\": false}, {\"check\": \"absent target\", \"actual\": [], \"expected\": [\"b\"], \"passed\": false}, {\"check\": \"supported\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty target\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty study\", \"actual\": [\"a\"], \"expected\": [\"a\"], \"passed\": true}, {\"check\": \"duplicate rows\", \"actual\": [\"a\"], \"expected\": [\"a\"], \"passed\": true}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}