What category of evidence is derived from at least one randomized controlled trial?

The category of evidence that is derived from at least one randomized controlled trial is classified as Ib. This classification is part of a hierarchy of evidence in clinical research, where different levels indicate the strength and reliability of the evidence available.

In evidence-based medicine, Level Ia corresponds to systematic reviews or meta-analyses of randomized controlled trials, while Level I represents evidence from at least one randomized controlled trial. Level Ib is more specific, indicating that the evidence comes from one or more well-designed randomized trials. This distinction highlights the importance of robust evidence obtained from rigorous study designs, like randomized controlled trials, which help in mitigating biases and providing reliable outcomes. Therefore, understanding the levels of evidence and their sources is crucial for making informed clinical decisions.