Question

experimental designs are almost identical to true experimental designs, but lacking one key ingredient:
assignment.

Answer 1

Experimental designs that are almost identical to true experimental designs but lack one key ingredient—random assignment—are often referred to as **quasi-experimental designs**. In true experimental designs, participants are randomly assigned to different groups (e.g., treatment and control) to ensure that any differences observed can be attributed to the treatment itself rather than other variables.

In quasi-experimental designs, researchers do not randomly assign participants to groups, which can lead to potential biases because the groups may differ in significant ways prior to the treatment. As a result, while quasi-experimental designs can still provide valuable insights and may allow for some level of causal inference, they are generally considered less robust than true experimental designs due to the potential for confounding variables affecting the outcomes.