Pat Dorsey is the guy who is at least partly responsible for democratising the use of Warren Buffett’s philosophy of moat in evaluating businesses. How, you may ask. He was instrumental in developing Morningstar’s economic moat ratings, as well as the methodology behind its framework for analysing competitive advantage. From 2000 to 2011, Dorsey was Director of Equity Research for Morningstar, where he led the growth of Morningstar’s equity research team from 20 to 90 analysts. Having authored two books — The Five Rules for Successful Stock Investing and The Little Book that Builds Wealth, Dorsey now manages money as the founder of Dorsey Asset Management, based out of Chicago. Who better than him to ask the tough questions around moats?