Welcome all for randomization

[Guest guest]

I hereby welcome all for the next topic in this series i. e. randomization. After the detailed discusion about study designs by Dr. Vijaya, we will have a short understanding of randomization.

My knowledge of Randomization

is enlightened by trainers of FHI biostatistics workshop, particularly Dr.

Rakesh aggarwal, Dr. Shinjini Bhatnagar Mark weaver and Chen. I ensure complete credit to my trainers.

Preamble & History:-

Randomization is the main bias-reducing technique.

Tracing back the history of randomization is difficult, but it

is found that RA Fischer, in 1920s developed randomization as basic principle

of experimentation particularly in agricultural field. Randomization

successfully entered healthcare sector in 1940s. Sir Austin Hill in 1950s used

and demonstrated randomization practices to support unbiased inferences.

Randomization is important to design good experiments, as it

substantially reduces the chance of bias which could arise if the subjects on

one intervention are in some way different from those on another.

However, it is not good enough just to randomize the subjects

to the treatment groups. It must be done throughout the whole experiment.

What is a bias?

Bias- Any systematic error in the design or conduct of a study that results

in a mistaken estimate

Selection Bias- Bias introduced by the way in which participants are

chosen for a study.

Confounding Bias- This occurs when an investigator falsely concludes

that a particular exposure is causally related to a variable without adjusting

for other variables that are known to affect the outcome.

What is randomization?

Random does not mean haphazard.

Randomization is the systematic process

of allocating a particular subject to a particular intervention, without any

premonition.

This is the most fundamental

aspect of doing RCT.

It consists of two processes

1. Generation of unpredictable random

allocation sequence.

2. Concealment of the generated

sequence until allocation.

The basic aim of doing

randomization is, `every participant in the study population should get equal

opportunity of getting selected or getting a particular intervention.'RegardsDr. Narendra BachewarAssistant ProffVNGMC, Yavatamal.