Experiments

The primary advantage of experiments is that they lend themselves to making causal attributions. Researchers often use pre-experimental designs because they do not have access to the features that would improve the design and must create at least the primary features of a more comprehensive experimental design. This chapter discusses three common pre-experimental designs. In the classic experiment, the experiment includes the independent variable, the pretest and posttest, and a randomized experimental and control group. This is now a true experimental design. The pre-, experimental, and quasi-experimental designs highlight the important components to consider when designing an experiment (independent and dependent variables, pretest/posttest, experimental and control groups, and random assignment). There are two other issues to keep in mind: the reliability and validity of the research design. Specifically related to experiments is the problem of subject bias, where subjects are aware they are being observed. Controlled Vocabulary Terms pre-experimental design; quasi-experiment; selection bias