Randomised controlled trial
This is a study in which a group of individuals with the condition of interest are randomly assigned at entry to the trial into one of two (or more) groups. Usually in clinical practice such groups will then receive different treatment regimes. Such trials may be single blind, in which the patient does not know which treatment he is getting, but are preferably double blind in which case the investigator/researcher too does not know what treatment the patient is receiving. This is because of the potential for both a powerful placebo effect and subjective bias in people. You could randomise institutions rather than people, and the principles involved are also used in animal and plant studies.
- Cohort study
- Case control study
- Randomised controlled trial
- PHRU on appraisal of a cohort study
- Social Research Methods website tutorial on cohort studies
- Wikipedia page on cohort studies
- Disease and exposure - includes sections on Odds ratio and Relative risk.
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