{"doi":"10.1093/ije/dyr095","title":"Magnitude of effects in clinical trials published in high-impact general medical journals","abstract":"<h4>Background</h4>Prestigious journals select for publication studies that are considered most important and informative. We aimed to examine whether high-impact general (HIG) medical journals systematically demonstrate more favourable results for experimental interventions compared with the rest of the literature.<h4>Methods</h4>We scrutinized systematic reviews of the Cochrane Database (Issue 4, 2009) and meta-analyses published in four general journals (2008-09). Eligible articles included ≥1 binary outcome meta-analysis(es) pertaining to effectiveness with ≥1 clinical trial(s) published in NEJM, JAMA or Lancet. Effect sizes in trials from NEJM, JAMA or Lancet were compared with those from other trials in the same meta-analyses by deriving summary relative odds ratios (sRORs). Additional analyses examined separately early- and late-published trials in HIG journals and journal-specific effects.<h4>Results</h4>A total of 79 meta-analyses including 1043 clinical trials were analysed. Trials in HIG journals had similar effects to trials in other journals, when there was large-scale evidence, but showed more favourable results for experimental interventions when they were small. When HIG trials had less than 40 events, the sROR was 1.64 [95% confidence interval (95% CI): 1.23-2.18). The difference was most prominent when small early trials published in HIG journals were compared with subsequent trials [sROR 2.68 (95% CI: 1.33-5.38)]. Late-published HIG trials showed no consistent inflation of effects. The patterns did not differ beyond chance between NEJM, JAMA or Lancet.<h4>Conclusions</h4>Small trials published in the most prestigious journals show more favourable effects for experimental interventions, and this is most prominent for early-published trials in such journals. No effect inflation is seen for large trials.","journal":"International Journal of Epidemiology","year":2011,"id":3707,"datarank":1.8771199907749347,"base_score":3.713572066704308,"endowment":3.713572066704308,"self_citation_contribution":0.5570358100056463,"citation_network_contribution":1.3200841807692885,"self_endowment_contribution":0.5570358100056463,"citer_contribution":1.3200841807692885,"corpus_percentile":null,"corpus_rank":null,"citation_count":40,"citer_count":29,"citers_with_citation_signal":18,"citers_with_endowment":18,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.0551,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2011-09-08","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":2427,"name":"Evangelos Evangelou","orcid":"0000-0002-5488-2999","position":1,"is_corresponding":false},{"id":148,"name":"John P. A. Ioannidis","orcid":"0000-0003-3118-6859","position":5,"is_corresponding":false},{"id":37698,"name":"Konstantinos CM Siontis","orcid":null,"position":0,"is_corresponding":true}],"reference_count":41,"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":[]}