{"doi":"10.1016/j.jclinepi.2014.09.007","title":"External validation of new risk prediction models is infrequent and reveals worse prognostic discrimination","abstract":"<h4>Objectives</h4>To evaluate how often newly developed risk prediction models undergo external validation and how well they perform in such validations.<h4>Study design and setting</h4>We reviewed derivation studies of newly proposed risk models and their subsequent external validations. Study characteristics, outcome(s), and models' discriminatory performance [area under the curve, (AUC)] in derivation and validation studies were extracted. We estimated the probability of having a validation, change in discriminatory performance with more stringent external validation by overlapping or different authors compared to the derivation estimates.<h4>Results</h4>We evaluated 127 new prediction models. Of those, for 32 models (25%), at least an external validation study was identified; in 22 models (17%), the validation had been done by entirely different authors. The probability of having an external validation by different authors within 5 years was 16%. AUC estimates significantly decreased during external validation vs. the derivation study [median AUC change: -0.05 (P < 0.001) overall; -0.04 (P = 0.009) for validation by overlapping authors; -0.05 (P < 0.001) for validation by different authors]. On external validation, AUC decreased by at least 0.03 in 19 models and never increased by at least 0.03 (P < 0.001).<h4>Conclusion</h4>External independent validation of predictive models in different studies is uncommon. Predictive performance may worsen substantially on external validation.","journal":"Journal of Clinical Epidemiology","year":2015,"id":9086,"datarank":0.9219493886503347,"base_score":6.1463292576688975,"endowment":6.1463292576688975,"self_citation_contribution":0.9219493886503347,"citation_network_contribution":0.0,"self_endowment_contribution":0.9219493886503347,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":466,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.0444,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2015-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":685,"name":"Ioanna Tzoulaki","orcid":"0000-0002-4275-9328","position":1,"is_corresponding":false},{"id":77979,"name":"Peter J. Castaldi","orcid":"0000-0001-9920-4713","position":2,"is_corresponding":false},{"id":148,"name":"John P. A. Ioannidis","orcid":"0000-0003-3118-6859","position":4,"is_corresponding":false},{"id":6426,"name":"George C.M. Siontis","orcid":"0000-0003-2128-9205","position":0,"is_corresponding":true}],"reference_count":93,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-03-01T18:20:47.508186Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}