Briefly state the primary problem that results from lack of randomization in an observational cohort study.

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Expert Solution

In observational cohort study the interventions takes place naturally, but in RCT or Randomized control trials, the interventions are controlled by the investigator.

The main problem which takes place in observational studies is due to the presence of Confounders variables (These are the variables which affect both dependent and independent variables) and due to the selection bias ( But it is prevented in RCT due to randomization and blinding). A confounder is a factor which is related to the intervention (e.g. treatment) as well as to the outcome and it can also affect both. For example in case of age- suppose in a study which is done to see the relationship between smoking (exposure) and lung cancer (outcome), age is considered as a factor, which can increase the incidence of the outcome. So if one of the groups (smokers or non-smokers) is of older population, the increase in the case of lung cancer may be influenced by age (which is a confounder), and not by the exposure that is smoking which is studied.

gladiator answered 1 year ago

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