These are the ‘gold standard’ of scientific studies because they are ‘controlled’. This means that steps have been taken to try to eliminate things that might have an influence beyond the specific thing being studied (as opposed to epidemiological studies).
The conclusions of a good quality RCT, then, can be quite a strong basis for claims.
RCTs are most often used to examine the effect of a drug or treatment on a person’s health. In RCTs for medical treatments, participants are separated into two groups; one is given the intervention and the other is given either a placebo (a dummy treatment that looks like the real one being tested, like a pill made of sugar) or the current best treatment, to find out whether the new treatment really is having an effect, and work out how big that effect is.
RCTs can be carried out in other areas of life too (for example, to test different teaching methods or new policies to tackle crime), though it is not always possible, practical or ethical to carry one out.
This page will help you work out if something is based on scientific research or not. It could be useful if you’ve received a response having asked for evidence, or [...]
‘In vitro’ (meaning ‘in glass’) studies are where scientists investigate chemicals, microorganisms (e.g. bacteria) or tissue (e.g. skin cells in isolation) in test tubes or petri dishes in a lab. [...]
No matter how exciting or compelling a new piece of scientific or medical research is, you should always ask: Is it peer reviewed? And if not, why not? Journals have [...]
Animal studies are a useful way of modelling what happens in the human body, so they are central to the development of new medicines and cures, and to understanding human [...]
There are a few basic types of scientific study that, once you know what they are, give you a much clearer way to question headlines or claims based on research. [...]
Epidemiologists (a kind of scientist) study how often diseases occur in different groups of people, and why. Their studies on populations will often report an association between a substance or [...]
