{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2012:2HQ2RNYTPDCABXEFKAJS2OWKKN","short_pith_number":"pith:2HQ2RNYT","canonical_record":{"source":{"id":"1212.0378","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"stat.AP","submitted_at":"2012-12-03T13:17:48Z","cross_cats_sorted":[],"title_canon_sha256":"22a33a64ce563bec582d8a3b33f7fca18f21ef6ed3f771056851933efe9da71c","abstract_canon_sha256":"435e1c4de50efc1836dece2b89fd5c3b807fe9e78bdc1982c2a7d44026760f3a"},"schema_version":"1.0"},"canonical_sha256":"d1e1a8b71378c400dc8550132d3aca5367a53e87e237b226b72f79496d310974","source":{"kind":"arxiv","id":"1212.0378","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1212.0378","created_at":"2026-05-18T03:39:17Z"},{"alias_kind":"arxiv_version","alias_value":"1212.0378v1","created_at":"2026-05-18T03:39:17Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1212.0378","created_at":"2026-05-18T03:39:17Z"},{"alias_kind":"pith_short_12","alias_value":"2HQ2RNYTPDCA","created_at":"2026-05-18T12:26:50Z"},{"alias_kind":"pith_short_16","alias_value":"2HQ2RNYTPDCABXEF","created_at":"2026-05-18T12:26:50Z"},{"alias_kind":"pith_short_8","alias_value":"2HQ2RNYT","created_at":"2026-05-18T12:26:50Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2012:2HQ2RNYTPDCABXEFKAJS2OWKKN","target":"record","payload":{"canonical_record":{"source":{"id":"1212.0378","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"stat.AP","submitted_at":"2012-12-03T13:17:48Z","cross_cats_sorted":[],"title_canon_sha256":"22a33a64ce563bec582d8a3b33f7fca18f21ef6ed3f771056851933efe9da71c","abstract_canon_sha256":"435e1c4de50efc1836dece2b89fd5c3b807fe9e78bdc1982c2a7d44026760f3a"},"schema_version":"1.0"},"canonical_sha256":"d1e1a8b71378c400dc8550132d3aca5367a53e87e237b226b72f79496d310974","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T03:39:17.685696Z","signature_b64":"VkyOcA/JQOehtmPSlWZNsq5GXVvZxjkvG4YHYH/8D0//weApxQOFOX0Kr5nku83Es51FjeOKYU0UWjUg6kIbDw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"d1e1a8b71378c400dc8550132d3aca5367a53e87e237b226b72f79496d310974","last_reissued_at":"2026-05-18T03:39:17.685150Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T03:39:17.685150Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1212.0378","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T03:39:17Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"MQRVBKKvj8b4JLiUoeSHBHA4WUlynXkc46tKJ9MeDcFDJ9CACUN8v16Qc2z2M3ZKR/OKV7wy5ukMU0E+n2QDDQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-05T21:27:11.974705Z"},"content_sha256":"fa45e7ae4377ba63fe438291179cb8a5a469eac753135ec0ac501dd0c31d013b","schema_version":"1.0","event_id":"sha256:fa45e7ae4377ba63fe438291179cb8a5a469eac753135ec0ac501dd0c31d013b"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2012:2HQ2RNYTPDCABXEFKAJS2OWKKN","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Joint Assessment of the Differential Item Functioning and Latent Trait Dimensionality of Students' National Tests","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"stat.AP","authors_text":"Francesco Bartolucci, Michela Gnaldi, Silvia Bacci","submitted_at":"2012-12-03T13:17:48Z","abstract_excerpt":"Within the educational context, students' assessment tests are routinely validated through Item Response Theory (IRT) models which assume unidimensionality and absence of Differential Item Functioning (DIF). In this paper, we investigate if such assumptions hold for two national tests administered in Italy to middle school students in June 2009: the Italian Test and the Mathematics Test. To this aim, we rely on an extended class of multidimensional latent class IRT models characterised by: (i) a two-parameter logistic parameterisation for the conditional probability of a correct response, (ii)"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1212.0378","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T03:39:17Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"nCOnPqvOBbX7+e4wJNDAegTtR6Jp1RsSG9dWK40qdahwTpuuzOeogu8E0SMUjrxscNFCIbfiCNZ/uP1NQPqdCQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-05T21:27:11.975535Z"},"content_sha256":"610c64a1d6f6319b1b61d19e651c6b6e5ab51fac520d2d9257be26b33f120d09","schema_version":"1.0","event_id":"sha256:610c64a1d6f6319b1b61d19e651c6b6e5ab51fac520d2d9257be26b33f120d09"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/2HQ2RNYTPDCABXEFKAJS2OWKKN/bundle.json","state_url":"https://pith.science/pith/2HQ2RNYTPDCABXEFKAJS2OWKKN/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/2HQ2RNYTPDCABXEFKAJS2OWKKN/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-06-05T21:27:11Z","links":{"resolver":"https://pith.science/pith/2HQ2RNYTPDCABXEFKAJS2OWKKN","bundle":"https://pith.science/pith/2HQ2RNYTPDCABXEFKAJS2OWKKN/bundle.json","state":"https://pith.science/pith/2HQ2RNYTPDCABXEFKAJS2OWKKN/state.json","well_known_bundle":"https://pith.science/.well-known/pith/2HQ2RNYTPDCABXEFKAJS2OWKKN/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2012:2HQ2RNYTPDCABXEFKAJS2OWKKN","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"435e1c4de50efc1836dece2b89fd5c3b807fe9e78bdc1982c2a7d44026760f3a","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"stat.AP","submitted_at":"2012-12-03T13:17:48Z","title_canon_sha256":"22a33a64ce563bec582d8a3b33f7fca18f21ef6ed3f771056851933efe9da71c"},"schema_version":"1.0","source":{"id":"1212.0378","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1212.0378","created_at":"2026-05-18T03:39:17Z"},{"alias_kind":"arxiv_version","alias_value":"1212.0378v1","created_at":"2026-05-18T03:39:17Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1212.0378","created_at":"2026-05-18T03:39:17Z"},{"alias_kind":"pith_short_12","alias_value":"2HQ2RNYTPDCA","created_at":"2026-05-18T12:26:50Z"},{"alias_kind":"pith_short_16","alias_value":"2HQ2RNYTPDCABXEF","created_at":"2026-05-18T12:26:50Z"},{"alias_kind":"pith_short_8","alias_value":"2HQ2RNYT","created_at":"2026-05-18T12:26:50Z"}],"graph_snapshots":[{"event_id":"sha256:610c64a1d6f6319b1b61d19e651c6b6e5ab51fac520d2d9257be26b33f120d09","target":"graph","created_at":"2026-05-18T03:39:17Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"paper":{"abstract_excerpt":"Within the educational context, students' assessment tests are routinely validated through Item Response Theory (IRT) models which assume unidimensionality and absence of Differential Item Functioning (DIF). In this paper, we investigate if such assumptions hold for two national tests administered in Italy to middle school students in June 2009: the Italian Test and the Mathematics Test. To this aim, we rely on an extended class of multidimensional latent class IRT models characterised by: (i) a two-parameter logistic parameterisation for the conditional probability of a correct response, (ii)","authors_text":"Francesco Bartolucci, Michela Gnaldi, Silvia Bacci","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"stat.AP","submitted_at":"2012-12-03T13:17:48Z","title":"Joint Assessment of the Differential Item Functioning and Latent Trait Dimensionality of Students' National Tests"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1212.0378","kind":"arxiv","version":1},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:fa45e7ae4377ba63fe438291179cb8a5a469eac753135ec0ac501dd0c31d013b","target":"record","created_at":"2026-05-18T03:39:17Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"435e1c4de50efc1836dece2b89fd5c3b807fe9e78bdc1982c2a7d44026760f3a","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"stat.AP","submitted_at":"2012-12-03T13:17:48Z","title_canon_sha256":"22a33a64ce563bec582d8a3b33f7fca18f21ef6ed3f771056851933efe9da71c"},"schema_version":"1.0","source":{"id":"1212.0378","kind":"arxiv","version":1}},"canonical_sha256":"d1e1a8b71378c400dc8550132d3aca5367a53e87e237b226b72f79496d310974","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"d1e1a8b71378c400dc8550132d3aca5367a53e87e237b226b72f79496d310974","first_computed_at":"2026-05-18T03:39:17.685150Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T03:39:17.685150Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"VkyOcA/JQOehtmPSlWZNsq5GXVvZxjkvG4YHYH/8D0//weApxQOFOX0Kr5nku83Es51FjeOKYU0UWjUg6kIbDw==","signature_status":"signed_v1","signed_at":"2026-05-18T03:39:17.685696Z","signed_message":"canonical_sha256_bytes"},"source_id":"1212.0378","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:fa45e7ae4377ba63fe438291179cb8a5a469eac753135ec0ac501dd0c31d013b","sha256:610c64a1d6f6319b1b61d19e651c6b6e5ab51fac520d2d9257be26b33f120d09"],"state_sha256":"ebf0d3a9ca8199c8f8729aa5654047058c36a0c780a855aad17075808498d523"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"2mOsFgmUuf8VXS2sMIYT2yGAsFLBnG8l4jOpERC/zou5aJxH24veqj9dV9tYphsPtz6TewEEtSTb0bAMyrRKDQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-05T21:27:11.979840Z","bundle_sha256":"1e5353563ded826fc4418ef71a864b31a92f6f40d8179c1b891a0b26e72fc952"}}