2.2.2. Screening for experimental and quasiexperimental research
In the second stage, the studies were screened according to the research method. Experimental studies (including the pretest-posttest equivalent-group, posttest-only equivalent-groups, and randomized matched subjects and posttest-only control-group designs) and quasi-experimental studies (including the pretest-posttest nonequivalent-groups and counterbalanced
designs; see Ary, Jacobs, & Razavieh, 2002; Best & Kahn, 1998, for a reference) were included. Conceptual analysis or research reviews, case studies and qualitative research, survey research, and pre-experimental studies were all excluded at this stage. At the completion of this stage there remained 182 articles.