Impact and Dynamics of Portfolio Assessment and Traditional Assessment in a College Physics Course Timothy F. Slater, 1 Joseph M. Ryan, 2 Sara L. Samson 3 1 Network Montana Project, Department of Mathematical Sciences, Montana State University, Bozeman, Montana 59717 2 Research Consulting Center, Arizona State University–West, Phoenix, Arizona 85069 3 Center for Excellence in the Assessment of Student Learning, College of Education, University of South Carolina, Columbia, South Carolina 29208 Received 1 June 1995; revised 12 August 1996; accepted 10 September 1996 Abstract: Popular belief in alternative assessment procedures suggests that the use of student portfolios can help learners successfully organize and integrate newly acquired scientific knowledge. This two-group comparison study documents the use of student created portfolios in an algebra-based, college-level, introductory physics course. Sixteen students were assessed primarily using a portfolio-style assessment procedure. Nineteen students were assessed primarily using traditional, objective examinations. Both groups were given the same cumulative, multiple-choice final examination. All students com- pleted a pre– and post–self-report survey of achievement in physics. There were no significant differences in learner achievement between the two groups on the final examination or on the self-report of achieve- ment given before and after instruction. Analysis of two focus group discussions did, however, suggest that students assessed by portfolios feel less anxious about learning physics, devote considerable time to read- ing and studying outside of class, internalize and personalize the content material, and enjoy the learning experience. The results of this study suggest that portfolio-style assessment procedures support student achievement at least at the same level as traditional assessment procedures and appear to have additional benefits. J Res Sci Teach 34: 255–271, 1997. Many educators have been introducing portfolio and performance assessments in a variety of classroom learning environments in response to the need for more authentic and equitable science assessment strategies (Arter & Spandel, 1992; Collins, 1992; O’Neil, 1992; Slater, 1994, 1996; Slater & Ryan, 1993). There are, however, only a limited number of studies that have looked at the effect portfolio assessment has on traditional examination performance (Herman & Winters, 1994). Almost no comparison research exists in the realm of alternative science ed- ucation assessment. Recommendations for the use of portfolio assessment may seem faddish in the absence of research evidence demonstrating that such assessment actually supports and en- courages students’ learning. JOURNAL OF RESEARCH IN SCIENCE TEACHING VOL. 34, NO. 3, PP. 255–271 (1997) © 1997 by the National Association for Research in Science Teaching Published by John Wiley & Sons, Inc. CCC 0022-4308/97/030255-17 Correspondence to: T.F. Slater