What is a key feature distinguishing RCTs from quasi-experimental studies?

A key feature that distinguishes randomized controlled trials (RCTs) from quasi-experimental studies is the implementation of randomization. Randomization is a critical methodological component in RCTs that ensures participants are assigned to treatment or control groups by chance, which minimizes bias and helps control for confounding variables. This allows for a more rigorous assessment of causal relationships between interventions and outcomes.

In contrast, quasi-experimental studies do not use random assignment. Instead, they may rely on pre-existing groups or allow participants to self-select into groups, which can introduce biases and limit the ability to draw definitive causal conclusions. The absence of randomization in quasi-experimental designs makes it more challenging to establish a clear cause-and-effect relationship, as the groups may differ in ways that influence the outcomes independent of the intervention being assessed. Thus, the hallmark of RCTs—randomization—provides a stronger foundation for making inferences about the effectiveness of an intervention compared to quasi-experimental designs.