Explained: What are randomized controlled trials, how do they work?

Source: The post is based on the article “Explained: What are randomized controlled trials, how do they work?” published in Indian Express on 15th July 2022

What is the News?

Economist and Nobel laureate Michael R Kremer has said that for a diverse country like India Randomized Controlled Trials(RCTs) must be carried out at multiple sites for better analysis and to see differences across states.

What are Randomized Controlled Trials(RCTs)?

RCTs involve dividing a population into smaller groups, in order to comparatively see the outcomes of an external stimulus. 

For example, if the aim of a study is to understand whether a free grains distribution scheme helped improve the nutrition levels among people living in a district, researchers will first create two groups within the population, and then put people into those groups randomly.

– One group (called the control group) does not receive the grains or the external stimulus, while the other group (treatment group) does. 

– After a designated period of time, details of how both the groups are doing would be collected. In this way, the goal is to understand what is the overall impact of introducing something new could be.

Nobel Prize: Micheal R.Kremer and fellow economists Abhijit Banerjee and Esther Duflo won the 2019 Nobel Prize winner in Economics. They had made use of RCT for their research on poverty. 

What are the criticisms against the use of RCTs?

Firstly, Angus Deaton, the winner of the Economics Nobel in 2015 said RCTs do not equalize two groups and warned against over-reliance on RCTs to frame policies.

– For instance, there may be more women in one group, or one group may have more people having some kind of distinctiveness that affects the result. As a result, the outcomes may not give an accurate view.

Secondly, RCTs cannot be used to study something after it has happened, they need to be planned beforehand. 

Thirdly, RCTs show results for a particular population in an area. It may not be proof that the same results will be achieved elsewhere especially if the sample size is not big or the trial deals with a very specific kind of population subgroup.