Page 1 of 2: Epidemiology

solo · Credits: 518 My Scrapbook

randomisation in experimental studies ensures that:
1.selection occurs by chance
2.treatment and control grps are alike in all respect except treatment
3.bias in obsevation is eliminated
4.placebo effects are eliminated
i thought the answer is (2) but the answer is given as (1).
anybody,please give the correct answer with explanation.
-solo

drnikhil1 · Credits: 3853 My Scrapbook

ans is 1 , 2 AND 4
about 3 bias in observation is eliminated by blinding
about 4

shaina · Credits: 15083 My Scrapbook

i think the ans is (2)

younaw · Credits: 396 My Scrapbook

answer is 1) bcoz of these reasons

second option cannot be the answer as treatment or control group wil be alike even if u dont do randomization as they may or may not know the drug given.

option 3 is also wrong bcoz bias in observation can still be there if it is open label study as both the investigators know the drug give even after randomization

option 4 is also wrong bcoz randomization is followed even in Bio-equivalence studies, and placebo effect can exsist even after randomization.

option 1) bcoz its just done as selection should not be done human, as he can favour his reference drug for good healthy volunteer in appearnce and lab tests, hence it should be left for computer to decide.

ratnakar_potla · Credits: 5703 My Scrapbook My Reading List 2 Books

Though it may sound strange...........i dont think that was a good question. because options two and one are equal in sense. May be the setter was too literal in context.......
second option says both groups are same in all respects which is literally not possible. so then one is a choice!!!!!!!!!!

younaw · Credits: 396 My Scrapbook

may be

mickey_p · Credits: 652 My Scrapbook

Ratnakar.... you have hit the nail on the head!! Good deduction!

Selection bias and confounding are linked.... its just that they occur at two different times ina study. A selection bias at the initial stage of a study leads to a confounding bias during the analysis stage later on.

Randomization reduces selection bias and thus ensures that whatever confounding factors that there may be in the subjects are randomly distributed, hence confounding is minimized (it is never eliminated!).

From the exam perspective....randomization is primarly done to reduce confounding...i.e. groups are similar to each other with respect to all the factors except the one under study

Ans 2 is correct
Dr Manish

jayanta · Credits: 34192 My Scrapbook My Reading List 45 Books

ANSWER IS 2.

abuye · Credits: 121 My Scrapbook

i go for choice one. allocation to treatment or control groups is by just a mere chance.about 2, not necessarily alike iin all characters.

vanshu17oct1 · Credits: 2828 My Scrapbook

Randomized control trial

In a randomized control trial people with a disease or at risk of disease are randomized into two or more groups.Randomized is expected to equalize the distribution of all major demographic characteristics such as age, sex, and socioeconomic status.To ensure that this is the case,known confounders should still be measured.Howeve,because of randomization with a large sample size,unknown confounders will likely to distribute themselves equally among the groups and thus play little role in the results obtained.One group is subjected to the intervention being evaluated, usually a treatment, while controls are given either an inactive treatment(placebo) or current standard treatment. So there is difference in treatments among groups.

So answer 2 is correct

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