Classroom demonstrations of the regression to the mean effect

Several years ago, I (Karylowski, 1985) developed a classroom demonstration of the regression toward the mean effect (RTME)--a source of bias in assessing the effects of any intervention preceded by an initial screening procedure and a difficult concept for students without a statistical background to grasp. The procedure is highly concrete and strictly psychological in nature, is applicable in both small and large classes, and does not require any statistical background. It facilitates discussion of reliability and the relationship between reliability and the RTME. I will present new empirical data assessing the effectiveness of this demonstration in teaching research methods.