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, cross-sectional, 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.