What is a key characteristic of a quasi-experimental study?

A quasi-experimental study is characterized by the manipulation of independent variables to assess their effect on dependent variables while typically lacking random assignment to treatment and control groups. This means that while researchers do implement an intervention or treatment (indicating manipulation of variables), these studies do not use randomization to assign participants to different groups.

By including specific interventions or changes, quasi-experimental studies can establish a cause-and-effect relationship to some extent, even though the absence of randomization may introduce potential biases. For instance, if researchers are exploring the impact of a new teaching method in a classroom setting, they might apply the method to one class while leaving another class unchanged. This manipulation helps researchers observe the effects of the intervention, thus fulfilling one of the critical features of quasi-experimental designs.

This understanding of quasi-experimental studies is crucial in recognizing how they differ from purely experimental designs, which require both manipulation and random assignment to control for confounding variables.