When Consensus Choice Dominates Individualism: Jensen's Inequality and Collective Decisions under Uncertainty

Working Paper: NBER ID: w15172

Authors: Charles F. Manski

Abstract: Research on collective provision of private goods has focused on distributional considerations. This paper studies a class of problems of decision under uncertainty in which the argument for collective choice emerges from the mathematics of aggregating individual payoffs. Consider decision making when each member of a population has the same objective function, which depends on an unknown state of nature. If agents knew the state of nature, they would make the same decision. However, they may have different beliefs or may use different decision criteria. Hence, they may choose different actions even though they share the same objective. Let the set of feasible actions be convex and the objective function be concave in actions, for all states of nature. Then Jensen's inequality implies that consensus choice of the mean privately-chosen action yields a larger aggregate payoff than does individualistic decision making, in all states of nature. If payoffs are transferable, the aggregate payoff from consensus choice may be allocated to Pareto dominate individualistic decision making, in all states of nature. I develop these ideas. I also use Jensen's inequality to show that a planner with the power to assign actions to the members of the population should not diversify. Finally, I give a version of the collective choice result that holds with consensus choice of the median rather than mean action.

Keywords: collective choice; individual decision-making; Jensen's inequality; uncertainty; Pareto dominance

JEL Codes: D7; D81; H42


Causal Claims Network Graph

Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.


Causal Claims

CauseEffect
mean privately chosen action (D70)higher aggregate payoff (C79)
collective choice (D70)Pareto dominate individualistic decision-making (D79)
mean treatment assigned to all individuals (C90)better outcomes (I14)

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