Essentials of Research Design and Methodology

GEOFFREY MARCZYK, JD, PHD, is Assistant Professor at Widener University’s Institute for Graduate Clinical Psychology in Chester, Pennsylvania.

DAVID DEMATTEO, JD, PHD, is a behavioral scientist at the Treatment Research Institute at the University of Pennsylvania in Philadelphia, Pennsylvania.

DAVID FESTINGER, PHD, is a behavioral scientist at the Treatment Resarch Institute at the University of Pennsylvania in Philadelphia, Pennsylvania.