{"abstract":"A carryover covariate follows assigned treatment or disappears during an untreated period without a documented washout.","category":"Causal analysis data contracts","checks":8,"contract":"Rows [subject,period,assigned,received,washed_out] have unique subject-period pairs. Treatments are A/B or None. The synthetic protocol defines carryover as the most recent actually received treatment since the last documented washout, persisting through untreated periods. Return sorted [subject,period,carryover] rows, with carryover evaluated before current receipt and after current washout. This is a categorical design encoding, not a pharmacokinetic claim.","evaluation_group":"model-414e28279397a294","failed_approach":"Using immediate previous receipt corrects noncompliance but treats an untreated period as if it washed out prior exposure.","family":"z-causal_inference-crossover-carryover-history","id":"FA-12681","implementations":{"attempt":{"sha256":"e15ddac916e11ff7d0d9f684d0da90a1853d85772357c865f1fe7e7c9961a1b1","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows):\n    history = {}\n    result = []\n    for subject, period, assigned, received, washed_out in sorted(rows):\n        if washed_out:\n            history[subject] = None\n        result.append([subject, period, history.get(subject)])\n        history[subject] = received\n    return result\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('actual receipt overrides assignment', solve([['s',N,'A','B',False],['s',N+1,'A','A',False]]), [['s',N,None],['s',N+1,'B']])\ncheck('untreated period preserves carryover', solve([['s',N,'A','A',False],['s',N+1,None,None,False],['s',N+2,'B','B',False]]), [['s',N,None],['s',N+1,'A'],['s',N+2,'A']])\ncheck('washout clears before current receipt', solve([['s',N,'A','A',False],['s',N+1,'B','B',True],['s',N+2,None,None,False]]), [['s',N,None],['s',N+1,None],['s',N+2,'B']])\ncheck('subjects have independent histories', solve([['s',N,'A','A',False],['t',N,'B','B',False],['s',N+1,None,None,False],['t',N+1,None,None,False]]), [['s',N,None],['s',N+1,'A'],['t',N,None],['t',N+1,'B']])\ncheck('input order does not determine history', solve([['s',N+1,'B','B',False],['s',N,'A','A',False]]), [['s',N,None],['s',N+1,'A']])\ncheck('no prior receipt means no carryover', solve([['s',N,'A',None,False],['s',N+1,'B','B',False]]), [['s',N,None],['s',N+1,None]])\ncheck('empty design', solve([]), [])\ncheck('washout without new receipt remains clear', solve([['s',N,'A','A',False],['s',N+1,None,None,True],['s',N+2,'B','B',False]]), [['s',N,None],['s',N+1,None],['s',N+2,None]])\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":"9e317c78c0cc3ee0617d2fb2be24d81162d06efc01703c85fb3b95eb8255b607","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows):\n    history = {}\n    result = []\n    for subject, period, assigned, received, washed_out in sorted(rows):\n        if washed_out:\n            history[subject] = None\n        result.append([subject, period, history.get(subject)])\n        if assigned is not None:\n            history[subject] = assigned\n    return result\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('actual receipt overrides assignment', solve([['s',N,'A','B',False],['s',N+1,'A','A',False]]), [['s',N,None],['s',N+1,'B']])\ncheck('untreated period preserves carryover', solve([['s',N,'A','A',False],['s',N+1,None,None,False],['s',N+2,'B','B',False]]), [['s',N,None],['s',N+1,'A'],['s',N+2,'A']])\ncheck('washout clears before current receipt', solve([['s',N,'A','A',False],['s',N+1,'B','B',True],['s',N+2,None,None,False]]), [['s',N,None],['s',N+1,None],['s',N+2,'B']])\ncheck('subjects have independent histories', solve([['s',N,'A','A',False],['t',N,'B','B',False],['s',N+1,None,None,False],['t',N+1,None,None,False]]), [['s',N,None],['s',N+1,'A'],['t',N,None],['t',N+1,'B']])\ncheck('input order does not determine history', solve([['s',N+1,'B','B',False],['s',N,'A','A',False]]), [['s',N,None],['s',N+1,'A']])\ncheck('no prior receipt means no carryover', solve([['s',N,'A',None,False],['s',N+1,'B','B',False]]), [['s',N,None],['s',N+1,None]])\ncheck('empty design', solve([]), [])\ncheck('washout without new receipt remains clear', solve([['s',N,'A','A',False],['s',N+1,None,None,True],['s',N+2,'B','B',False]]), [['s',N,None],['s',N+1,None],['s',N+2,None]])\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"},"fixed":{"sha256":"e59219fe9526b33b933bb63b7ecb77db44d1cb65b546e06a9f73815e50b5adf2","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows):\n    history = {}\n    result = []\n    for subject, period, assigned, received, washed_out in sorted(rows):\n        if washed_out:\n            history[subject] = None\n        result.append([subject, period, history.get(subject)])\n        if received is not None:\n            history[subject] = received\n    return result\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('actual receipt overrides assignment', solve([['s',N,'A','B',False],['s',N+1,'A','A',False]]), [['s',N,None],['s',N+1,'B']])\ncheck('untreated period preserves carryover', solve([['s',N,'A','A',False],['s',N+1,None,None,False],['s',N+2,'B','B',False]]), [['s',N,None],['s',N+1,'A'],['s',N+2,'A']])\ncheck('washout clears before current receipt', solve([['s',N,'A','A',False],['s',N+1,'B','B',True],['s',N+2,None,None,False]]), [['s',N,None],['s',N+1,None],['s',N+2,'B']])\ncheck('subjects have independent histories', solve([['s',N,'A','A',False],['t',N,'B','B',False],['s',N+1,None,None,False],['t',N+1,None,None,False]]), [['s',N,None],['s',N+1,'A'],['t',N,None],['t',N+1,'B']])\ncheck('input order does not determine history', solve([['s',N+1,'B','B',False],['s',N,'A','A',False]]), [['s',N,None],['s',N+1,'A']])\ncheck('no prior receipt means no carryover', solve([['s',N,'A',None,False],['s',N+1,'B','B',False]]), [['s',N,None],['s',N+1,None]])\ncheck('empty design', solve([]), [])\ncheck('washout without new receipt remains clear', solve([['s',N,'A','A',False],['s',N+1,None,None,True],['s',N+2,'B','B',False]]), [['s',N,None],['s',N+1,None],['s',N+2,None]])\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-crossover-carryover-history","generated_at":"2026-09-29T14:38:59.175403+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.","repair":"Within each subject, process periods in order; clear history at documented washout, emit the pre-period carryover label, then update history only for actual treatment receipt.","root_cause":"Sequence assignment or immediate previous receipt substitutes for persistent actual exposure history in the supplied crossover design.","sha256":"915c91c8f06f057cf89c9aeb4b700ef2b5bfc4ca30af701b437864e0d6fdf5b0","title":"Crossover carryover coding forgets actual prior exposure across untreated periods · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":38.93,"exit_code":1,"observations":[{"actual":[["s",1,null],["s",2,"B"]],"check":"actual receipt overrides assignment","expected":[["s",1,null],["s",2,"B"]],"passed":true},{"actual":[["s",1,null],["s",2,"A"],["s",3,null]],"check":"untreated period preserves carryover","expected":[["s",1,null],["s",2,"A"],["s",3,"A"]],"passed":false},{"actual":[["s",1,null],["s",2,null],["s",3,"B"]],"check":"washout clears before current receipt","expected":[["s",1,null],["s",2,null],["s",3,"B"]],"passed":true},{"actual":[["s",1,null],["s",2,"A"],["t",1,null],["t",2,"B"]],"check":"subjects have independent histories","expected":[["s",1,null],["s",2,"A"],["t",1,null],["t",2,"B"]],"passed":true},{"actual":[["s",1,null],["s",2,"A"]],"check":"input order does not determine history","expected":[["s",1,null],["s",2,"A"]],"passed":true},{"actual":[["s",1,null],["s",2,null]],"check":"no prior receipt means no carryover","expected":[["s",1,null],["s",2,null]],"passed":true},{"actual":[],"check":"empty design","expected":[],"passed":true},{"actual":[["s",1,null],["s",2,null],["s",3,null]],"check":"washout without new receipt remains clear","expected":[["s",1,null],["s",2,null],["s",3,null]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"actual receipt overrides assignment\", \"actual\": [[\"s\", 1, null], [\"s\", 2, \"B\"]], \"expected\": [[\"s\", 1, null], [\"s\", 2, \"B\"]], \"passed\": true}, {\"check\": \"untreated period preserves carryover\", \"actual\": [[\"s\", 1, null], [\"s\", 2, \"A\"], [\"s\", 3, null]], \"expected\": [[\"s\", 1, null], [\"s\", 2, \"A\"], [\"s\", 3, \"A\"]], \"passed\": false}, {\"check\": \"washout clears before current receipt\", \"actual\": [[\"s\", 1, null], [\"s\", 2, null], [\"s\", 3, \"B\"]], \"expected\": [[\"s\", 1, null], [\"s\", 2, null], [\"s\", 3, \"B\"]], \"passed\": true}, {\"check\": \"subjects have independent histories\", \"actual\": [[\"s\", 1, null], [\"s\", 2, \"A\"], [\"t\", 1, null], [\"t\", 2, \"B\"]], \"expected\": [[\"s\", 1, null], [\"s\", 2, \"A\"], [\"t\", 1, null], [\"t\", 2, \"B\"]], \"passed\": true}, {\"check\": \"input order does not determine history\", \"actual\": [[\"s\", 1, null], [\"s\", 2, \"A\"]], \"expected\": [[\"s\", 1, null], [\"s\", 2, \"A\"]], \"passed\": true}, {\"check\": \"no prior receipt means no carryover\", \"actual\": [[\"s\", 1, null], [\"s\", 2, null]], \"expected\": [[\"s\", 1, null], [\"s\", 2, null]], \"passed\": true}, {\"check\": \"empty design\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"washout without new receipt remains clear\", \"actual\": [[\"s\", 1, null], [\"s\", 2, null], [\"s\", 3, null]], \"expected\": [[\"s\", 1, null], [\"s\", 2, null], [\"s\", 3, null]], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.285,"exit_code":1,"observations":[{"actual":[["s",1,null],["s",2,"A"]],"check":"actual receipt overrides assignment","expected":[["s",1,null],["s",2,"B"]],"passed":false},{"actual":[["s",1,null],["s",2,"A"],["s",3,"A"]],"check":"untreated period preserves carryover","expected":[["s",1,null],["s",2,"A"],["s",3,"A"]],"passed":true},{"actual":[["s",1,null],["s",2,null],["s",3,"B"]],"check":"washout clears before current receipt","expected":[["s",1,null],["s",2,null],["s",3,"B"]],"passed":true},{"actual":[["s",1,null],["s",2,"A"],["t",1,null],["t",2,"B"]],"check":"subjects have independent histories","expected":[["s",1,null],["s",2,"A"],["t",1,null],["t",2,"B"]],"passed":true},{"actual":[["s",1,null],["s",2,"A"]],"check":"input order does not determine history","expected":[["s",1,null],["s",2,"A"]],"passed":true},{"actual":[["s",1,null],["s",2,"A"]],"check":"no prior receipt means no carryover","expected":[["s",1,null],["s",2,null]],"passed":false},{"actual":[],"check":"empty design","expected":[],"passed":true},{"actual":[["s",1,null],["s",2,null],["s",3,null]],"check":"washout without new receipt remains clear","expected":[["s",1,null],["s",2,null],["s",3,null]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"actual receipt overrides assignment\", \"actual\": [[\"s\", 1, null], [\"s\", 2, \"A\"]], \"expected\": [[\"s\", 1, null], [\"s\", 2, \"B\"]], \"passed\": false}, {\"check\": \"untreated period preserves carryover\", \"actual\": [[\"s\", 1, null], [\"s\", 2, \"A\"], [\"s\", 3, \"A\"]], \"expected\": [[\"s\", 1, null], [\"s\", 2, \"A\"], [\"s\", 3, \"A\"]], \"passed\": true}, {\"check\": \"washout clears before current receipt\", \"actual\": [[\"s\", 1, null], [\"s\", 2, null], [\"s\", 3, \"B\"]], \"expected\": [[\"s\", 1, null], [\"s\", 2, null], [\"s\", 3, \"B\"]], \"passed\": true}, {\"check\": \"subjects have independent histories\", \"actual\": [[\"s\", 1, null], [\"s\", 2, \"A\"], [\"t\", 1, null], [\"t\", 2, \"B\"]], \"expected\": [[\"s\", 1, null], [\"s\", 2, \"A\"], [\"t\", 1, null], [\"t\", 2, \"B\"]], \"passed\": true}, {\"check\": \"input order does not determine history\", \"actual\": [[\"s\", 1, null], [\"s\", 2, \"A\"]], \"expected\": [[\"s\", 1, null], [\"s\", 2, \"A\"]], \"passed\": true}, {\"check\": \"no prior receipt means no carryover\", \"actual\": [[\"s\", 1, null], [\"s\", 2, \"A\"]], \"expected\": [[\"s\", 1, null], [\"s\", 2, null]], \"passed\": false}, {\"check\": \"empty design\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"washout without new receipt remains clear\", \"actual\": [[\"s\", 1, null], [\"s\", 2, null], [\"s\", 3, null]], \"expected\": [[\"s\", 1, null], [\"s\", 2, null], [\"s\", 3, null]], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":40.2,"exit_code":0,"observations":[{"actual":[["s",1,null],["s",2,"B"]],"check":"actual receipt overrides assignment","expected":[["s",1,null],["s",2,"B"]],"passed":true},{"actual":[["s",1,null],["s",2,"A"],["s",3,"A"]],"check":"untreated period preserves carryover","expected":[["s",1,null],["s",2,"A"],["s",3,"A"]],"passed":true},{"actual":[["s",1,null],["s",2,null],["s",3,"B"]],"check":"washout clears before current receipt","expected":[["s",1,null],["s",2,null],["s",3,"B"]],"passed":true},{"actual":[["s",1,null],["s",2,"A"],["t",1,null],["t",2,"B"]],"check":"subjects have independent histories","expected":[["s",1,null],["s",2,"A"],["t",1,null],["t",2,"B"]],"passed":true},{"actual":[["s",1,null],["s",2,"A"]],"check":"input order does not determine history","expected":[["s",1,null],["s",2,"A"]],"passed":true},{"actual":[["s",1,null],["s",2,null]],"check":"no prior receipt means no carryover","expected":[["s",1,null],["s",2,null]],"passed":true},{"actual":[],"check":"empty design","expected":[],"passed":true},{"actual":[["s",1,null],["s",2,null],["s",3,null]],"check":"washout without new receipt remains clear","expected":[["s",1,null],["s",2,null],["s",3,null]],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"actual receipt overrides assignment\", \"actual\": [[\"s\", 1, null], [\"s\", 2, \"B\"]], \"expected\": [[\"s\", 1, null], [\"s\", 2, \"B\"]], \"passed\": true}, {\"check\": \"untreated period preserves carryover\", \"actual\": [[\"s\", 1, null], [\"s\", 2, \"A\"], [\"s\", 3, \"A\"]], \"expected\": [[\"s\", 1, null], [\"s\", 2, \"A\"], [\"s\", 3, \"A\"]], \"passed\": true}, {\"check\": \"washout clears before current receipt\", \"actual\": [[\"s\", 1, null], [\"s\", 2, null], [\"s\", 3, \"B\"]], \"expected\": [[\"s\", 1, null], [\"s\", 2, null], [\"s\", 3, \"B\"]], \"passed\": true}, {\"check\": \"subjects have independent histories\", \"actual\": [[\"s\", 1, null], [\"s\", 2, \"A\"], [\"t\", 1, null], [\"t\", 2, \"B\"]], \"expected\": [[\"s\", 1, null], [\"s\", 2, \"A\"], [\"t\", 1, null], [\"t\", 2, \"B\"]], \"passed\": true}, {\"check\": \"input order does not determine history\", \"actual\": [[\"s\", 1, null], [\"s\", 2, \"A\"]], \"expected\": [[\"s\", 1, null], [\"s\", 2, \"A\"]], \"passed\": true}, {\"check\": \"no prior receipt means no carryover\", \"actual\": [[\"s\", 1, null], [\"s\", 2, null]], \"expected\": [[\"s\", 1, null], [\"s\", 2, null]], \"passed\": true}, {\"check\": \"empty design\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"washout without new receipt remains clear\", \"actual\": [[\"s\", 1, null], [\"s\", 2, null], [\"s\", 3, null]], \"expected\": [[\"s\", 1, null], [\"s\", 2, null], [\"s\", 3, null]], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}