How to Ensure that the Control and Treated Patients are Similar in all Important Respects
It is essential that the treated and control patients are similar in order that any differences in outcome can be attributed to the treatment and not to other factors. Thus far everyone agrees, but how to obtain similar groups is open to some discussion. In this chapter we discuss the two classical methods: (1) using the patient as his own control (cross-over studies) and (2) random (chance) allocation of patients to distinct and concurrently treated groups. Randomisation is expected to result in the groups being similar. The futility of using historical controls is discussed in section 8.2.3; this chapter deals mainly with the advantages, disadvantages, and methods of randomisation.
KeywordsAnticoagulant Therapy Important Respect Random Number Table Nuisance Variable Restricted Randomisation
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