Media type: E-Article Title: The Performance of Different Lookback Periods and Sources of Information for Charlson Comorbidity Adjustment in Medicare Claims Contributor: Zhang, James X.; Iwashyna, Theodore J.; Christakis, Nicholas A. imprint: Ovid Technologies (Wolters Kluwer Health), 1999 Published in: Medical Care Language: English DOI: 10.1097/00005650-199911000-00005 ISSN: 0025-7079 Keywords: Public Health, Environmental and Occupational Health Origination: Footnote: