"The implications for planning are ambiguous. On the one hand, the optimal allocation under increasing returns will not be obtained under free markets. In fact, as I have already remarked, the competitive equilibrium is not even viable, and the outcome will be some kind of imperfect competition. But optimal allocation under increasing returns is difficult. For one thing, the optimisation requires the use of integer programming, a procedure intrinsically more complex than linear programming, and impossible to carry out for large systems even with the most powerful computers. Even more serious are the data demands. The information needed is widely dispersed among the industries and cannot be effectively communicated. It is for these reasons that decentralised decision-making with some element of monopoly is likely to be more efficient."
Kenneth Arrow

January 1, 1970