Đang chuẩn bị nút TẢI XUỐNG, xin hãy chờ
Tải xuống
Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí hóa học quốc tế đề tài :Investigating the missing data mechanism in quality of life outcomes: a comparison of approaches | Health and Quality of Life Outcomes BioMed Central Research Investigating the missing data mechanism in quality of life outcomes a comparison of approaches Shona Fielding 1 Peter M Fayers1 2 and Craig R Ramsay3 Open Access Address Section of Population Health University of Aberdeen UK 2Department of Cancer Research and Molecular Medicine Faculty of Medicine Norwegian University of Science and Technology Trondheim Norway and 3Health Services Research Unit University of Aberdeen UK Email Shona Fielding - s.fielding@abdn.ac.uk Peter M Fayers - p.fayers@abdn.ac.uk Craig R Ramsay-c.r.ramsay@abdn.ac.uk Corresponding author Published 22 June 2009 Received 22 January 2009 Health and Quality of Life Outcomes 2009 7 57 doi 10.1186 1477-7525-7-57 Accepted 22 June 2009 This article is available from http www.hqlo.com content 7 1 57 2009 Fielding et al licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http creativecommons.Org licenses by 2.0 which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Background Missing data is classified as missing completely at random MCAR missing at random MAR or missing not at random MNAR . Knowing the mechanism is useful in identifying the most appropriate analysis. The first aim was to compare different methods for identifying this missing data mechanism to determine if they gave consistent conclusions. Secondly to investigate whether the reminder-response data can be utilised to help identify the missing data mechanism. Methods Five clinical trial datasets that employed a reminder system at follow-up were used. Some quality of life questionnaires were initially missing but later recovered through reminders. Four methods of determining the missing data mechanism were applied. Two response data scenarios were considered. Firstly immediate data only secondly all observed responses including .
