“Improvement in students’ critical thinking skills and dispositions cannot be a matter of implicit expectation…educators must take steps to make critical thinking objectives explicit in courses and also include them in both pre-service and in-service training and faculty development.”

From a meta-analysis, published in the Review of Educational Research, which examined 117 studies involving 20,298 participants.  Investigators reported an average positive effect size (g+) of 0.341 and a standard deviation of 0.610, with fluctuations in CT effect sizes related to the type of instructional intervention and pedagogy applied. The conceptualization of critical thinking used in this meta-analysis research is the APA Delphi construct.

The same construct as is used in the development of Insight Assessment tests and measures, namely that critical thinking is the process of purposeful self-regulatory judgment focused on deciding what to believe or what to do.

Reference: “Instructional Interventions Affecting Critical Thinking Skills and Dispositions: A Stage 1 Meta-Analysis.”  Philip C Abrami; Robert M Bernard; Evgueni Borokhovski; Anne Wade; et al, Review of Educational Research; Dec 2008; 78, 4; Research Library. pg. 1102.