Remember that iconic scene in the matrix where Morpheus asks Neo to choose the red pill or the blue pill? That’s how I like to think of RCT’s.
Basically the researcher is “Morpheus” and the study subject is “Neo”, but instead of just 1 Neo choosing the red/blue pill we have a few. Each Neo is randomly assigned either the red or blue pill. Morpheus then sits back and watches what happens to the Neo’s and we see by the end of it who is more content – the Neo living life in blissful ignorance in the Matrix or the one steeped in reality.
Which is basically what RCT’s do. They assess how different interventions/treatments affect two different groups by following up participants. When done well, it provides the best evidence on the cause and effect relationship by studying it in real time. (temporal sequence)
There is an experimental group given the intervention/treatment (Neo leaving the Matrix) and the comparison group (controls) that gets a placebo or the current conventional treatment (Neo in the Matrix). They are then followed up to assess how effective the new intervention/treatment is in comparison to the current standard/placebo group. (Is Neo more content out of the Matrix or in?)
However unlike Neo in the Matrix, there is no choice involved and the individuals involved are randomly assigned.
Why? To avoid any selection bias by the testers choosing individuals who may have better outcomes and to ensure that both groups are as similar as possible therefore being able to distribute the confounding factors.
What are confounding factors?
It is basically any other variable that can affect your dependent variable.
For example, if we are doing a study on a sedentary lifestyle causing weight gain. The independent variable here is the sedentary lifestyle while the dependent variable is weight gain. And the confounding factors can be anything from stress, diet, food portions, genetics and metabolism – all of which can affect weight gain (dependent variable). The hope is that by randomising it, we will get an equal amount of these other confounding factors in every group therefore giving us a clearer picture on the intervention being studied.
Despite being the best method, RCT’s still has some short-comings. They tend to be expensive, time consuming and you could argue that if a person is in an RCT – they are probably more likely to be compliant therefore not really giving us a real world experience.
365 days of public health 