Is randomization same as Random sampling?

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Is randomization same as Random sampling?

NO, it is not.

Just looking at the word we can

know that Random sampling is a method of sampling, not randomization.

Unfortunately we don't come across random sampling and randomization in the

same study design.

Sampling is choosing our

experimental population from the target population. If we are choosing our

subjects irrespective of any variable (like age, gender, height, lipid profile,

BP, etc), we are doing a Random sampling. Practically random sampling is not

100% successful as our target population is ill-defined.

Whereas, in a Randomized

controlled trial we are applying some Inclusion and Exclusion criteria. The

Study population must pass through all these criteria. So this is some

privileged population, and not representative of our pure target population.

This can be called as convenience sample. And randomization is done after

confirmation of sample size, just before assigning the interventions.

With the help of Randomization we

can make and compare various subgroups within our study population.

If we have done random sampling,

we can apply our inferences directly to the target population. But in RCT we

can only generalize our inferences upto the study population. If we want to

apply our results beyond randomized population, we need some fairly strong

assumptions.Dr. Narendra BachewarAssistant ProfessorVNGMC, Yavatmal