Bloomberg Opinion columnist Barry Ritholtz interviews Andrew Ang, who leads BlackRock’s factor-based strategies group. Ang has published widely on equities, fixed income, asset and factor allocation, and alternative assets; his book “Asset Management: A Systematic Approach to Factor Investing” was published by Oxford University Press. Prior to joining BlackRock, Ang was chair of Columbia Business School’s finance and economics division; he earned his Ph.D. in finance and M.S. in statistics from Stanford University.