After reading this chapter, you should be able to:

1. Define and identify a quasi-experiment and a quasi-independent variable.
2. Identify and describe two one-group quasi-experimental research designs: the posttest-only and pretest-posttest designs.
3. Identify and describe two nonequivalent control group quasi-experimental research designs: the posttest-only and pretest-posttest designs.
4. Identify and describe three time-series quasi-experimental research designs: basic, interrupted, and control designs.
5. Identify and describe three developmental quasi-experimental research designs: longitudinal, crosssectional, and cohort-sequential designs.
6. Define the single-case experimental design.
7. Identify and describe three types of single-case research designs: the reversal, multiple-baseline, and changing-criterion designs.
8. Identify in a graph the stability and magnitude of a dependent measure, and explain how each is related to the internal validity of a single-case design.
9. Identify three ways that researchers can strengthen the external validity of a result using a single-case design.