We study a voting model in which the evaluation of social welfare must be based on information about agents’ top choices plus general qualitative background conditions on preferences. The former is elicited individually, while the latter is not. We apply this ‘frugal aggregation’ approach to budget allocation problems, relying on the specific assumptions of convexity and separability of preferences.
We propose a unifying solution concept of ex-ante Condorcet winners which incorporates the epistemic assumptions of particular frugal aggregation models. We show that for the case of convex preferences, the ex-ante Condorcet approach naturally leads to refinement of the Tukey median. By contrast, in the case of separably convex preferences, the same approach leads to a different solution, the L1-median, i.e. the minimization of the sum of the L1-distances to the agents’ tops.