Question

What are strengths and weaknesses of each of the major types of epidemiologic study?

-Randomized controlled trial

– Cohort

– Case-control

Answer 1

-Randomized controlled trial is ''gold standard' in avidance based medicine, representing the highest level of evidence

Strengths- I) by using this method we are able to assign and administor treatment or interventions in a precise and controlled way.

Ii) It is only type of of study which is able to establish causation.

Iii) It decreases patient or oberver bias.

Iv) By the use of RCT we can have subgroup analysis, which enhances usefulness for clinical practices.

Weakness- I) It is a coastly process

ii) It is logistically challenging process I.e., difficulty arises in its organization.

iii) Results may not always mimic real life treatment situation.

-Cohort is a group of individuals which shares common characters during different time such as birth and graduation or any other event.

Advantages- i) Cohort studies clearly tells about temporal sequence between exposure and outcome.

Ii) This is a reasonable approach to establish past exposure.

Iii) Cohort studies allows to calculate evidence of disesdi in exposure groups.

Iv) It also facilitates study of rare exposure.

Disadvantages- i) It is not good for rare disease.

Ii) Sometimes it may be difficult to identify an appropriate exposed cohort or appropriate comparison group.

Iii) This study is not good for disease with long latency.

Iv) It may be very expensive and time consuming.

- Case control study is a type of study in which we look back in time to find risk between exposure and outcome.

Advantages- i) They are very efficient for rare diseases or diseases with long latency period.

Ii) These methods are less coastly and less time consuming.

Iii) This method is advantageous while studying dynamic populations.

Disadvantages- i) These studies subjects to selection bias .

Ii) These studies are efficient for rare exposures.

Iii) They generally do not allows calculation of absolute risk.