Roger G. Ibbotson is among the best-known scholars and practitioners in the field of asset allocation. I had the privilege of working with him at Ibbotson Associates. I spoke with him on the subject a while back and thought the present was a good time to share some of his insights. What follows is a lightly edited transcript of our discussion. Larry Cao, CFA: Many in the industry still ask, how important is asset allocation? Can you walk us through that? What percentage of performance is explained by asset allocation? Roger G. Ibbotson: Back in the old days, people considered you an investment genius if the market ... (full story)