{"abstract":"Slice aggregation gives each nonempty slice equal weight.","category":"Evaluation metric aggregation","checks":7,"contract":"Slices map names to [correct,total]; return total correct divided by total examples, or 0 when empty.","contract_signature":"slices","evaluation_group":"w3-eval-slice-weighting","failed_approach":"Skipping empty slices still leaves nonempty slice means equally weighted rather than pooling their supports.","family":"w3-evaluation-metric-aggregation-slice-weighting","id":"FA-100036","implementations":{"attempt":{"sha256":"9dc1ea9139512dd7574271f7ed01d3deb24136e4d25c078f9cd18f9099ffde8e","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(slices):\n    vals=[c/t for c,t in slices.values() if t]; return sum(vals)/len(vals) if vals else 0\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('unequal slice sizes',solve({'a':[N,N],'b':[0,1]}),N/(N+1))\ncheck('fixed unequal slices',solve({'a':[3,4],'b':[0,1]}),.6)\ncheck('perfect slices',solve({'a':[N,N],'b':[2,2]}),1)\ncheck('empty',solve({}),0)\ncheck('zero support',solve({'a':[0,0]}),0)\ncheck('one nonempty',solve({'a':[1,2],'b':[0,0]}),.5)\ncheck('all incorrect',solve({'x':[0,N]}),0)\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":"41405c6444df223cba731e7a0ee42e6611abb9ee9a5f006d7d6c1ab1871d2ba8","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(slices):\n    return sum(c/t for c,t in slices.values() if t)/len(slices) if slices else 0\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('unequal slice sizes',solve({'a':[N,N],'b':[0,1]}),N/(N+1))\ncheck('fixed unequal slices',solve({'a':[3,4],'b':[0,1]}),.6)\ncheck('perfect slices',solve({'a':[N,N],'b':[2,2]}),1)\ncheck('empty',solve({}),0)\ncheck('zero support',solve({'a':[0,0]}),0)\ncheck('one nonempty',solve({'a':[1,2],'b':[0,0]}),.5)\ncheck('all incorrect',solve({'x':[0,N]}),0)\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":"Inputs are finite toy labels and scores; this defines no benchmark protocol, production metric library, or model quality claim. 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":"w3-evaluation-metric-aggregation-slice-weighting","generated_at":"2026-09-30T16:48:30.840869+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A small explicit evaluation contract makes aggregation behavior reproducible across labeled examples.","root_cause":"Per-slice scores are averaged equally even though the contract weights examples.","sha256":"358ad4535ea5acc78213991548acc6eeec46d73f7a024467196299d9e23e7637","title":"Slice aggregation gives each nonempty slice equal weight · case 01","variant":1,"variant_policy":"The fixture code references N, supplied as 1 through 5. Fixed boundary checks may repeat. These records share one mechanism and must remain together in evaluation splits.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":30.586,"exit_code":1,"observations":[{"actual":0.5,"check":"unequal slice sizes","expected":0.5,"passed":true},{"actual":0.375,"check":"fixed unequal slices","expected":0.6,"passed":false},{"actual":1.0,"check":"perfect slices","expected":1,"passed":true},{"actual":0,"check":"empty","expected":0,"passed":true},{"actual":0,"check":"zero support","expected":0,"passed":true},{"actual":0.5,"check":"one nonempty","expected":0.5,"passed":true},{"actual":0.0,"check":"all incorrect","expected":0,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"unequal slice sizes\", \"actual\": 0.5, \"expected\": 0.5, \"passed\": true}, {\"check\": \"fixed unequal slices\", \"actual\": 0.375, \"expected\": 0.6, \"passed\": false}, {\"check\": \"perfect slices\", \"actual\": 1.0, \"expected\": 1, \"passed\": true}, {\"check\": \"empty\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"zero support\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"one nonempty\", \"actual\": 0.5, \"expected\": 0.5, \"passed\": true}, {\"check\": \"all incorrect\", \"actual\": 0.0, \"expected\": 0, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":28.986,"exit_code":1,"observations":[{"actual":0.5,"check":"unequal slice sizes","expected":0.5,"passed":true},{"actual":0.375,"check":"fixed unequal slices","expected":0.6,"passed":false},{"actual":1.0,"check":"perfect slices","expected":1,"passed":true},{"actual":0,"check":"empty","expected":0,"passed":true},{"actual":0.0,"check":"zero support","expected":0,"passed":true},{"actual":0.25,"check":"one nonempty","expected":0.5,"passed":false},{"actual":0.0,"check":"all incorrect","expected":0,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"unequal slice sizes\", \"actual\": 0.5, \"expected\": 0.5, \"passed\": true}, {\"check\": \"fixed unequal slices\", \"actual\": 0.375, \"expected\": 0.6, \"passed\": false}, {\"check\": \"perfect slices\", \"actual\": 1.0, \"expected\": 1, \"passed\": true}, {\"check\": \"empty\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"zero support\", \"actual\": 0.0, \"expected\": 0, \"passed\": true}, {\"check\": \"one nonempty\", \"actual\": 0.25, \"expected\": 0.5, \"passed\": false}, {\"check\": \"all incorrect\", \"actual\": 0.0, \"expected\": 0, \"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."}}