What is posttest- only design?

A posttest-only design is a type of experimental research design where participants are randomly assigned to either a treatment group or a control group, and measurements are taken only after the intervention has occurred. This approach allows researchers to assess the effects of the intervention without any pretest measurements, reducing potential biases related to pretest influences. It is often used for its simplicity and efficiency, particularly when pretesting could affect participants' responses. However, it may limit the ability to assess baseline differences between groups.