Worst-Case Voting When the Stakes Are High

No. 5: AAAI-22 Technical Tracks 5

Volume

Proceedings of the AAAI Conference on Artificial Intelligence, 36

AAAI Technical Track on Game Theory and Economic Paradigms

We study the additive distortion of social choice functions in the implicit utilitarian model, and argue that it is a more appropriate metric than multiplicative distortion when an alternative that confers significant social welfare may exist (i.e., when the stakes are high). We define a randomized analog of positional scoring rules, and present a rule which is asymptotically optimal within this class as the number of alternatives increases. We then show that the instance-optimal social choice function can be efficiently computed. Next, we take a beyond-worst-case view, bounding the additive distortion of prominent voting rules as a function of the best welfare attainable in an instance. Lastly, we evaluate the additive distortion of a range of rules on real-world election data.

10.1609/aaai.v36i5.20443