  Voting by sequential elimination is a low-communication voting protocol:
voters play in sequence and eliminate one or more of the remaining candidates,
until only one remains. While the fairness and efficiency of such protocols
have been explored, the impact of strategic behaviour has not been addressed.
We model voting by sequential elimination as a game. Given a fixed elimination
sequence, we show that the outcome is the same in all subgame-perfect Nash
equilibria of the corresponding game, and is polynomial-time computable. We
measure the loss of social welfare due to strategic behaviour, with respect to
the outcome under sincere behaviour, and with respect to the outcome maximizing
social welfare. We give tight bounds for worst-case ratios, and show using
experiments that the average impact of manipulation can be much lower than in
the worst case.
