Describe the nonequivalent control group design and nonequivalent control group pretest- posttest design, and discuss the advantages of having a control group.

LEARNING OBJECTIVES
Describe single-case experimental designs and discuss reasons to use this design.

Describe the one-group posttest-only design.

Describe the one-group pretest-posttest design and the associated threats to internal validity that may occur: history, maturation, testing, instrument decay, and regression toward the mean.

Describe the nonequivalent control group design and nonequivalent control group pretest- posttest design, and discuss the advantages of having a control group.

Distinguish between the interrupted time series design and control series design.

Describe cross-sectional, longitudinal, and sequential research designs, including the advantages and disadvantages of each design.

Define cohort effect.