Our discussion last week about representatives of the League of California Cities urging CalPERS, the state’s huge pension fund for public employees, to juice up investment returns generated a lot of interesting feedback. It is clear that public-pension funds need some help. Rather than offer specific investment recommendations, I am going to make some suggestions to help them think about what they should be considering when reviewing their own portfolios. It is important for managers and public representatives to understand what they know, what they don’t know, and what they can’t possibly know.