What are the standards of quality used when assessing experimental and quasi-experimental research designs?
Experimental design = Experimental designs are considered the more stringent of the two designs described here, due to their random assignment of participants to conditions, and should be used over quasi-experimental design whenever possible . In general, experiments are evaluated on the basis of two related criteria: The adequacy of their hypothetical counterfactual. (If truly random assignment of participants to conditions is used, the natural differences which exist in individuals should be evenly distributed between the experimental treatment group and control groups. Therefore these groups should, in theory, be comparable to each other at the start of the experiment.) How well their design addresses the four types of validity described below. Quasi-experimental design = As with experiments, quasi-experiments are generally evaluated on the basis of two related criteria: The adequacy of the hypothetical counterfactual. (As random assignment of participants to conditions is not used
