Nghiên cứu hồi cứu: nghiên cứu hồi cứu. Nghiên cứu hồi cứu: Một thuật ngữ chung cho các nghiên cứu, trong đó tất cả các sự kiện quan tâm xảy ra trước khi bắt đầu nghiên cứu, và kết quả dựa trên tìm kiếm về phía sau trong thời gian. | Retrospective cohort study See retrospective study. Retrospective study A general term for studies in which all the events of interest occur before the onset of the study and findings are based on looking backwards in time. Most common is the case-control study in which comparisons are made between individuals who have a particular disease or condition the cases and individuals who do not have the disease the controls . A sample of cases is selected from the population of individuals who have the disease of interest and a sample of controls is taken from those individuals known not to have the disease. Information about possible risk factors for the disease is then obtained retrospectively for each person in the study by examining past records by interviewing each person and or interviewing their relatives or by some other method. In order to make the cases and controls otherwise comparable they are frequently matched on characteristics known to be related strongly to both disease and exposure leading to a matched case-control study. Age sex and socioeconomic status are examples of commonly used matching variables. Also commonly encountered is the retrospective cohort study in which a past cohort of individuals is identified from previous information for example employment records and their subsequent mortality or morbidity determined and compared with the corresponding experience of some suitable control group. Morton R. F. Hebel J. R. and McCarter R. J. 1990 A Study Guide to Epidemiology and Biostatistics 3rd edn Aspen Gaithersburg MD. Reverse causality Synonym for protopathic bias. Reverse J-shaped distribution See j-shaped distribution. Ridge regression A method of regression analysis designed to overcome the possible problem of multicollinearity among the explanatory variables. Such multicollinearity makes it difficult to estimate the separate effects of variables on the response. By allowing regression estimates to be biased this form of regression results in
