Yale professor Roger Ibbotson and Research Affiliates founder Rob Arnott debated the challenges and opportunities of timing the market at the 2015 Schwab IMPACT conference.  As reported by Financial Advisor, the two speakers generally agreed that “the stocks that are the most popular will do the worst, as Ibbotson said, or, as Arnott put it, “you just have to find the flows and do the opposite.” But Arnott argued for focusing on underlying valuation and that “we should weigh companies based on their macroeconomic footprint. . . Use the size of a business to contratrade against the markets’ bets.” While Ibbotson didn’t necessarily disagree, he added a major caveat: “If you go against what everybody else is doing, you can do well . . . [but] people can’t really follow that kind of advice.”