For Anupama: Welcome all for randomization

[Guest guest]

Yes Anupama,

As you say there are different methods of randomization line you mentioned.

Amongst the stated methods, Lots, tables and computerized are randomization

methods.

But the Other method i.e. Picking up every 5th person is a non-random method

masking as random. It is a false method.

I have already pointed out that a randomization method should satisfy two aims

1. Generate a random sequence

2. Conceal the sequence until the time of assignment.

This last method of picking every 5th person clearly does not satisfy our second

aim. It seems that it will satisfy the first one, but it does not.

We will come to different methods of randomization in our future posts.

Regards

Dr. Narendra Bachewar

Assistant Professor

VNGMC, Yavatmal

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> From: Naren <naren_bachewar@...>

> Subject: Welcome all for randomization

> netrum

> Date: Saturday, 3 July, 2010, 4:54 AM

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> 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.

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> 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.

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> Preamble & History:-

> Randomization is the main bias-reducing technique.

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> 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.

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> 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.

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> What is a bias?

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

a mistaken estimate

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

for a study.

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> 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.

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> 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.

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> 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.

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> 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. '

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> Regards

> Dr. Narendra Bachewar

> Assistant Proff

> VNGMC, Yavatamal.

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