What is the Solomon four-group design?

The Solomon four-group design is a sophisticated experimental research strategy that assesses the impact of treatments while addressing potential biases introduced by pre-testing. This design involves four groups: two groups receive the treatment after a pre-test (one of which also gets a post-test), while the other two groups receive only the post-test, allowing researchers to compare both the effects of pre-testing and the treatment itself.

This structure is crucial because it helps determine whether any observed differences in outcomes can be attributed solely to the treatment, or if they are influenced by the act of pre-testing. By including groups with and without pre-tests, the Solomon four-group design provides a comprehensive understanding of how pre-testing can affect results, and it ensures that researchers can better isolate the treatment effect itself.

Other approaches, such as those focusing solely on comparing multiple control groups or limiting designs to qualitative data, do not encompass the same depth of analysis regarding pre-testing influence. Furthermore, the Solomon four-group design's design with more than two groups and the specific consideration of pre- and post-testing distinguishes it from simpler experimental designs that may only use treatment and control groups without this nuanced approach.