| Abstract |
Dr. T. S. Au
Social Hygiene Service, Department of Health, Hong Kong
The cohort study, case-control study and randomized control trial are commonly used in medical research. Each type has its own strength and weakness. All doctors, no matter whether they are actively involved in research or not, should be familiar with these study designs. Understanding the principles can help them to be more critical when reading medical journals.
Keywords : Case-control study, cohort, randomized control trial