Identifying outcome reporting bias in randomised trials on PubMed: review of publications and survey of authors.
OBJECTIVE: To examine the extent and nature of outcome reporting bias in a broad cohort of published randomised trials. DESIGN: Retrospective review of publications and follow up survey of authors. Cohort All journal articles of randomised trials indexed in PubMed whose primary publication appeared...
| Main Authors: | , |
|---|---|
| Format: | Journal article |
| Language: | English |
| Published: |
2005
|
| _version_ | 1797089354034708480 |
|---|---|
| author | Chan, A Altman, D |
| author_facet | Chan, A Altman, D |
| author_sort | Chan, A |
| collection | OXFORD |
| description | OBJECTIVE: To examine the extent and nature of outcome reporting bias in a broad cohort of published randomised trials. DESIGN: Retrospective review of publications and follow up survey of authors. Cohort All journal articles of randomised trials indexed in PubMed whose primary publication appeared in December 2000. MAIN OUTCOME MEASURES: Prevalence of incompletely reported outcomes per trial; reasons for not reporting outcomes; association between completeness of reporting and statistical significance. RESULTS: 519 trials with 553 publications and 10,557 outcomes were identified. Survey responders (response rate 69%) provided information on unreported outcomes but were often unreliable--for 32% of those who denied the existence of such outcomes there was evidence to the contrary in their publications. On average, over 20% of the outcomes measured in a parallel group trial were incompletely reported. Within a trial, such outcomes had a higher odds of being statistically non-significant compared with fully reported outcomes (odds ratio 2.0 (95% confidence interval 1.6 to 2.7) for efficacy outcomes; 1.9 (1.1 to 3.5) for harm outcomes). The most commonly reported reasons for omitting efficacy outcomes included space constraints, lack of clinical importance, and lack of statistical significance. CONCLUSIONS: Incomplete reporting of outcomes within published articles of randomised trials is common and is associated with statistical non-significance. The medical literature therefore represents a selective and biased subset of study outcomes, and trial protocols should be made publicly available. |
| first_indexed | 2024-03-07T03:02:55Z |
| format | Journal article |
| id | oxford-uuid:b18e04fc-8457-4a77-8f3f-8e1f9cda29e0 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T03:02:55Z |
| publishDate | 2005 |
| record_format | dspace |
| spelling | oxford-uuid:b18e04fc-8457-4a77-8f3f-8e1f9cda29e02022-03-27T04:04:57ZIdentifying outcome reporting bias in randomised trials on PubMed: review of publications and survey of authors.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:b18e04fc-8457-4a77-8f3f-8e1f9cda29e0EnglishSymplectic Elements at Oxford2005Chan, AAltman, D OBJECTIVE: To examine the extent and nature of outcome reporting bias in a broad cohort of published randomised trials. DESIGN: Retrospective review of publications and follow up survey of authors. Cohort All journal articles of randomised trials indexed in PubMed whose primary publication appeared in December 2000. MAIN OUTCOME MEASURES: Prevalence of incompletely reported outcomes per trial; reasons for not reporting outcomes; association between completeness of reporting and statistical significance. RESULTS: 519 trials with 553 publications and 10,557 outcomes were identified. Survey responders (response rate 69%) provided information on unreported outcomes but were often unreliable--for 32% of those who denied the existence of such outcomes there was evidence to the contrary in their publications. On average, over 20% of the outcomes measured in a parallel group trial were incompletely reported. Within a trial, such outcomes had a higher odds of being statistically non-significant compared with fully reported outcomes (odds ratio 2.0 (95% confidence interval 1.6 to 2.7) for efficacy outcomes; 1.9 (1.1 to 3.5) for harm outcomes). The most commonly reported reasons for omitting efficacy outcomes included space constraints, lack of clinical importance, and lack of statistical significance. CONCLUSIONS: Incomplete reporting of outcomes within published articles of randomised trials is common and is associated with statistical non-significance. The medical literature therefore represents a selective and biased subset of study outcomes, and trial protocols should be made publicly available. |
| spellingShingle | Chan, A Altman, D Identifying outcome reporting bias in randomised trials on PubMed: review of publications and survey of authors. |
| title | Identifying outcome reporting bias in randomised trials on PubMed: review of publications and survey of authors. |
| title_full | Identifying outcome reporting bias in randomised trials on PubMed: review of publications and survey of authors. |
| title_fullStr | Identifying outcome reporting bias in randomised trials on PubMed: review of publications and survey of authors. |
| title_full_unstemmed | Identifying outcome reporting bias in randomised trials on PubMed: review of publications and survey of authors. |
| title_short | Identifying outcome reporting bias in randomised trials on PubMed: review of publications and survey of authors. |
| title_sort | identifying outcome reporting bias in randomised trials on pubmed review of publications and survey of authors |
| work_keys_str_mv | AT chana identifyingoutcomereportingbiasinrandomisedtrialsonpubmedreviewofpublicationsandsurveyofauthors AT altmand identifyingoutcomereportingbiasinrandomisedtrialsonpubmedreviewofpublicationsandsurveyofauthors |