Dr. Smith is conducting a nonequivalent control group quasi-experiment. Results of a pretest show that members of the experimental and control group differ on the dependent variable. What can Dr. Smith do about this outcome?
A) match participants from the experimental and control groups on pretest scores and analyze only the data from the matched participants.
B) statistically control for those preexisting differences using an analysis of covariance.
C) conduct a pretest-posttest study using the experimental group participants and not use a control group at all.
D) conduct an interrupted time series analysis of experimental and control group posttest scores.

Question

Quizplus · Accepted Answer

One option for dealing with preexisting differences between the experimental and control group on the dependent variable is to statistically control for those differences using an analysis of covariance (ANCOVA). This allows the researcher to remove the effects of the preexisting differences from the analysis of the experimental manipulation. Matching participants or conducting a pretest-posttest study without a control group are not adequate solutions to this problem. Conducting an interrupted time series analysis may be useful in other contexts but does not address the issue of preexisting differences between groups.

Dr Smith Is Conducting a Nonequivalent Control Group Quasi-Experiment