Effectiveness of a personalized system of instruction in an algebra/trig sequence at the college level

A pre-test/post-test experimental model was used to study the effectiveness of a personalized system of instruction (PSI) in the algebra/trig sequence at the college level. Data were obtained from 777 students who completed a course in algebra, pre-calculus algebra, or trigonometry. Students were divided into control groups taught by the lecture-discussion method with one instructor per section and experimental groups taught by a modified Keller PSI plan. Both groups used the same text and syllabus. Using an analysis of covariance controlling for GPA, the mean gain score of the experimental group was significantly larger than the mean gain score of the control group for algebra (p = 0.056, N=503). The results were not significant for the other two classes.