David J. Reibstein is the William Stewart Woodside Professor and Professor of Marketing at the Wharton School. His research focuses on marketing metrics and their link to financial consequences, competitive marketing strategy, market segmentation, brand choice, and product line breadth. He has been published in every major marketing journal and has authored or co-authored numerous books. He served as the Executive Director of the Marketing Sciences Institute, and co-founded Wharton’s CMO Summit. Reibstein architected and teaches the Wharton Executive Education course on marketing metrics. He consults with leading businesses, including GE, Shell Oil, HP, Novartis, Johnson & Johnson, Merck, and Major League Baseball. He has served as Vice Dean and Director of Wharton’s Graduate Division, as visiting professor at Stanford and INSEAD, and as faculty member at Harvard. Reibstein was the co-founder of Shopzilla, one of the first product search engines, and serves on several corporate boards.