What type of study design is included in Level IIb evidence?

Level IIb evidence is characterized by well-designed quasi-experimental studies. These studies involve interventions where participants are not randomly assigned to groups, which differentiates them from randomized controlled trials. Quasi-experimental designs often use comparison groups and control for confounding variables, allowing researchers to draw conclusions about the efficacy of an intervention.

In quasi-experimental studies, researchers may implement an intervention and then compare the outcomes with another group that did not receive the intervention. This approach helps to establish evidence when randomization is not ethical or feasible, making it valuable in various clinical and educational settings.

While randomized controlled studies provide the strongest form of evidence due to their rigor, quasi-experimental designs still hold significant importance in the hierarchy of research evidence, especially in real-world applications where randomization might not be practical.