Glossary
Randomized controlled trial
A study that assigns participants by chance to different groups, so differences in results can be attributed to the intervention.
In a randomized controlled trial (RCT), participants, or sometimes clinics or classrooms, are randomly assigned either to receive the intervention being tested, such as an AI tool, or to a comparison group. Randomization balances other factors between the groups, so differences in outcomes are more likely to be caused by the intervention.
RCTs are considered the strongest standard evidence for whether a treatment, tool, or teaching method actually works. They are slower and costlier than other studies, and relatively few AI tools have been tested this way.
Even an RCT's result applies to the setting, population, and version of the tool tested. A positive trial in one hospital or school system may not carry over to another.
Read more: our explainer