Pre-experimental Designs

Pre-experimental designs are research schemes in which a subject or a group is observed after a treatment has been applied, in order to test whether the treatment has the potential to cause change. The prefix pre- conveys two different senses in which this type of design differs from experiments: (1) pre-experiments are a more rudimentary form of design relative to experiments, devised in order to anticipate any problems that experiments may later encounter vis-à-vis causal inference, and (2) pre-experiments are often preparative forms of exploration prior to engaging in experimental endeavors, providing cues or indications that an experiment is worth pursuing. Because pre-experiments typically tend to overstate rather than understate the presence of causal relations between variables, it is sometimes useful to run a pre-experiment ...