In choice experiments the investigator organizes profiles into systematically constructed choice sets where the profiles are designed on the basis of all attributes. When the number of attributes or attribute levels becomes large, the profiles in a single choice set may be too numerous for respondents to make precise decisions. We present strategies for reducing the number of profiles and the sizes of choice sets, and discuss the optimality of these designs using information per profile (IPP) as the optimality criterion. Designs where two-way and higher order interactions are estimated are particularly prone to requiring many profiles. The number of profiles may be reduced if it is only required that a subset of interactions be estimated. We provide designs in which only a subset of two-way and three-way interactions are estimated for factorial experiments.

Pallavi Chitturi is Professor of Statistics and Director of the Center for Statistical Analysis, Temple University, Philadelphia. Dr. Chitturi teaches statistics courses at The Fox School of Business at Temple University and for the Executive MBA programs in Philadelphia and Bogota, Colombia. She also teaches for the Executive Doctorate in Business Administration (EDBA) program at Fox, and serves as Associate Academic Director of the program. Dr. Chitturi’s research interests are in the areas of choice based conjoint analysis, experimental design, and quality assurance. She has been awarded numerous research grants that include 3 grants from the U.S. Navy’s Naval Logistics Readiness Research Center and one grant from the Office of The Vice-Provost for Research at Temple University. Dr. Chitturi has made several research presentations at national and international conferences, and has published articles in statistics and quality management journals. Dr. Chitturi has successfully supervised Ph.D. dissertations and published a book titled ‘Choice Based Conjoint Analysis – Models and Designs’ (co-authors Damaraju Raghavarao and James Wiley). Dr. Chitturi is a recipient of numerous teaching awards including the Musser Award for Excellence in Teaching, Lindback Award for Distinguished Teaching, Andrisani-Frank Undergraduate Teaching Award, and Crystal Apple Teaching Award.