{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,2]],"date-time":"2026-05-02T00:43:53Z","timestamp":1777682633051,"version":"3.51.4"},"reference-count":39,"publisher":"SAGE Publications","issue":"1","license":[{"start":{"date-parts":[[1996,1,1]],"date-time":"1996-01-01T00:00:00Z","timestamp":820454400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J Health Serv Res Policy"],"published-print":{"date-parts":[[1996,1]]},"abstract":"<jats:sec>\n                    <jats:title>Objectives:<\/jats:title>\n                    <jats:p>The introduction of an internal market in the British National Health Service (NHS) has highlighted the importance of developing appropriate, valid and timely measures of hospital activity, both for the purposes of specifying and monitoring contracts and for evaluating the success of the NHS reforms in general. This paper compares the validity of five case mix methods (Diagnosis Related Groups (DRGs); Healthcare Resource Groups (HRGs) versions 1 and 2; specialty classification; a simple age categorization) in predicting resource use.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods:<\/jats:title>\n                    <jats:p>Two data sets were used to compare different case mix methods. A 3% random sample (n \u2243 300 000) of the 1992\/3 Hospital Episodes Statistics was used to test their ability to predict variation in length of stay, and a second set of individually costed patient episodes from two hospitals (n \u2243 40 000) was used to test their ability to explain cost variation. Analysis of variance models were used to assess the fit of each of the case mix systems to test data and a simple significance test of differences in mean squared error between models was applied.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results:<\/jats:title>\n                    <jats:p>All case mix methods performed poorly on untrimmed data. When lengths of stay greater than 29 days were excluded, version 2 of HRGs explained 31% of total variance in length of stay and 25% of cost variation. DRGs explained less variance but performed better than HRGs version 1. For a typical hospital patient population consisting of a range of specialties, the difference in explanatory power between HRGs V2 and DRGs was statistically significant at the 5% level for sample sizes of approximately 2000 or greater. For individual specialties, the minimum sample size required for the difference between the groupers to be significant ranged from around 300 to over 2000.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions:<\/jats:title>\n                    <jats:p>The locally developed HRGs version 2 system appears to offer superior performance in terms of resource homogeneity to other currently available approaches. It is also more adaptable and cheaper than imported alternatives and has been formally endorsed by the UK medical Royal Colleges.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1177\/135581969600100104","type":"journal-article","created":{"date-parts":[[2018,2,1]],"date-time":"2018-02-01T10:53:45Z","timestamp":1517482425000},"page":"10-19","source":"Crossref","is-referenced-by-count":13,"title":["Case Mix Measurement in English Hospitals: An Evaluation of Five Methods for Predicting Resource Use"],"prefix":"10.1177","volume":"1","author":[{"given":"Neil","family":"S\u00f6derlund","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alastair","family":"Gray","sequence":"additional","affiliation":[{"name":"Centre for Sociolegal Studies, Wolfson College, University of Oxford"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ruairidh","family":"Milne","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"James","family":"Raftery","sequence":"additional","affiliation":[{"name":"National Case Mix Office, Winchester, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"179","published-online":{"date-parts":[[1996,1,1]]},"reference":[{"key":"bibr1-135581969600100104","doi-asserted-by":"publisher","DOI":"10.1177\/107755878203900101"},{"key":"bibr2-135581969600100104","doi-asserted-by":"publisher","DOI":"10.1177\/107755878203900201"},{"key":"bibr3-135581969600100104","doi-asserted-by":"publisher","DOI":"10.1016\/0277-9536(83)90276-9"},{"key":"bibr4-135581969600100104","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.pu.09.050188.002001"},{"key":"bibr5-135581969600100104","doi-asserted-by":"publisher","DOI":"10.1136\/jech.48.3.224"},{"key":"bibr6-135581969600100104","volume-title":"Costing for Contracting \u2014Acute Services. FDL (93) 51 Annex A","author":"NHS Management Executive","year":"1993"},{"key":"bibr7-135581969600100104","volume-title":"Steering group on health services information: Chairman: Mrs E Korner: A report on the collection and use of hospital clinical activity in the National Health Service","author":"Department of Health and Social Security","year":"1982"},{"key":"bibr8-135581969600100104","volume-title":"Manual of the international statistical classification of diseases, injuries and causes of death \u2014 ninth revision, 1975","author":"World Health Organization","year":"1977"},{"key":"bibr9-135581969600100104","volume-title":"Tabular list of the classification of surgical operations and procedures: Fourth revision","author":"Office of Population Censuses and Surveys","year":"1990"},{"key":"bibr10-135581969600100104","doi-asserted-by":"publisher","DOI":"10.1097\/00005650-198708000-00006"},{"key":"bibr11-135581969600100104","first-page":"65","volume":"25","author":"Hicks N","year":"1993","journal-title":"Health Trends"},{"key":"bibr12-135581969600100104","doi-asserted-by":"publisher","DOI":"10.1093\/oxfordjournals.pubmed.a042816"},{"key":"bibr13-135581969600100104","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.309.6961.1046"},{"key":"bibr14-135581969600100104","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.309.6961.1050"},{"key":"bibr15-135581969600100104","first-page":"119","volume":"13","author":"Wiley M M","year":"1992","journal-title":"Health Care Financing Review"},{"key":"bibr16-135581969600100104","doi-asserted-by":"publisher","DOI":"10.1016\/0168-8510(91)90048-3"},{"key":"bibr17-135581969600100104","volume-title":"DRGs: A guide to grouping and interpretation","author":"Jenkins L","year":"1990"},{"key":"bibr18-135581969600100104","volume-title":"Diagnosis related groups. 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