In a randomized controlled trial, the essential purpose of randomization is -

Ans. is 'c' i.e., To eliminate the selection bias o Experimental studies are of two types ? i) Randomized controlled trials ii) Non - Randomized Randomized controlled trials (RCT) o Randomization is the hea of RCT. o Randomization is a statistical procedure by which the paicipants are allocated into study group (in which intervention is given) and control group / reference group (in which intervention is not given). o It is woh noting that randomisation is done while dividing the paicipants into study group and control (reference) group, and not while selecting subjects for study, i.e. randomization is done after the sample of subjects has already been selected. o Therefor, each paicipant has 'equal and known chance' of falling into either study group or control group. o Randomization is an attempt to eliminate bias and allow comparability. o It will give the greatest confidence that the groups are comparable so that "like" can be compared with "like". o It ensures that the investigator has no control over allocation of paicipants to either study or control group, thus eliminating what is known as selection bias. o That means, by random allocation, every individual gets an equal chance of being allocated into either group, study (experimental) group or control (reference) group. o Unit of study in RCT: Patient o RCT is of two types: Concurrent parallel design: Comparisons are made between 2 groups: 1) Experimental group: Is exposed to specific medication or intervention 2) Reference group: Is not exposed to specific medication or intervention Crossover design: Comparisons are made between 2 groups: 1) Experimental group: Is exposed to specific medication or intervention Reference group: Is not exposed to specific medication or intervention Then the groups are crossed-over (exposed group now becomes non-exposed and vice-versa).