{"doi":"10.1136/bmj.310.6977.446","title":"Statistics notes: Calculating correlation coefficients with repeated observations: Part 1—correlation within subjects","abstract":null,"journal":"BMJ","year":1995,"id":599788,"datarank":1.0427658246598368,"base_score":6.951772164398911,"endowment":6.951772164398911,"self_citation_contribution":1.0427658246598368,"citation_network_contribution":0.0,"self_endowment_contribution":1.0427658246598368,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":1044,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1537279,"name":"Douglas G Altman","orcid":null,"position":1,"is_corresponding":false},{"id":1537278,"name":"J Martin Bland","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"Statistics notes: Calculating correlation coefficients with repeated observations: Part 1—correlation within subjects","abstract":"In an earlier Statistics Note1 we commented on the analysis of paired data where there is more than one observation per subject, as shown in table I. We pointed out that it could be highly misleading to analyse such data by combining repeated observations from several subjects and then calculating the correlation coefficient as if the data were a simple sample. This note is a response to several letters about the appropriate analysis for such data.\n\nView this table:\n\nTABLE I \nRepeated measurements of intramural pH and PaCO2 for eight subjects2\n\n\n\nThe choice of analysis for the data in table I depends on the question we want to …","is_dataset_classified":null,"base_score":6.951772164398911,"endowment":6.951772164398911,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"7873953","pmcid":"PMC2548822","openalex_id":"https://openalex.org/W2060932201","authors":[],"funders":[],"total_grants":0,"fwci":5.5898,"citation_percentile":0.96559905,"influential_citations":0,"citation_trend":[{"year":2012,"count":49},{"year":2013,"count":40},{"year":2014,"count":49},{"year":2015,"count":54},{"year":2016,"count":43},{"year":2017,"count":51},{"year":2018,"count":74},{"year":2019,"count":51},{"year":2020,"count":65},{"year":2021,"count":69},{"year":2022,"count":66},{"year":2023,"count":62},{"year":2024,"count":60},{"year":2025,"count":46},{"year":2026,"count":15}],"oa_status":"bronze","license":"http://www.bmj.com/company/legal-information/terms-conditions/legal-information/tdm-licencepolicy","oa_locations":[{"url":"https://www.bmj.com/content/bmj/310/6977/446.full.pdf","host_type":"journal"},{"url":"https://www.bmj.com/content/bmj/310/6977/446.full.pdf","host_type":"publisher"},{"url":"http://data.bmj.org/tdm/10.1136/bmj.310.6977.446","host_type":"publisher"},{"url":"https://syndication.highwire.org/content/doi/10.1136/bmj.310.6977.446","host_type":"publisher"},{"url":"https://doi.org/10.1136/bmj.310.6977.446","host_type":"journal"}],"fields_of_study":["Renal function and acid-base balance"],"mesh_terms":["Humans","Carbon Dioxide","Analysis of Variance","Hydrogen-Ion Concentration","Partial Pressure","Research","Statistics as Topic"],"keywords":["Statistics","Correlation","Correlation coefficient","Mathematics","Fisher transformation","Correlation ratio","Geometry"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Quality Education"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-07-29T11:15:09.969859Z","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":[]}