Manipulability measures of common social choice functions

All social choice functions are manipulable when more than two alternatives are available. I evaluate the manipulability of the Borda count, plurality rule, minimax set, and uncovered set. Four measures of manipulability are defined and computed stochastically for small numbers of agents and alternatives. <p> Social choice rules derived from the minimax and uncovered sets are found to be relatively immune to manipulation whether a sole manipulating agent has complete knowledge or absolutely no knowledge of the preferences of the others. The Borda rule is especially manipulable if the manipulating agent has complete knowledge of the others. <!--ID="" Acknowledgements. Without the guidance of Fuad D. Aleskerov, this project would not have begun. Without the aid of Richard D. McKelvey, it would not have been completed. Measures F1 and F2 were invented by Aleskerov9, and the expected measure was proposed by McKelvey. Funding for this paper was provided by Summer Undergraduate Research Fellowships 1995 of California Institute of Technology. Computational resources were provided by Caltech's Undergraduate Computer Science Laboratory.-->