SODA is not strategy free. Even if you make the assumption that candidate preferences are honest because dishonesty will be detected and punished by voters -- an assumption which puts the system beyond the reach of the Gibbard-Satterthwaite proof -- the fact remains that you can construct strategic scenarios.
However, it seems to me that SODA is not just a less-strategic system than most others, but radically so. Unlike Approval, semi-honest approval strategy is not something voters must deal with at least implicitly. But like approval, non-semi-honest strategy is relegated to a tiny minority of voters in a tiny minority of cases. The system can deal with all the commonly-discussed strategic problems, including chicken, center squeeze, and honest cycle. I honestly suspect that strategy under SODA would be favored less than half as often as any other good deterministic system I know of, including Approval, Asset, Condorcet (various), IRV, Median, and Range. So, how would you set out to make this idea demonstrable or falsifiable? What rigorous statement about strategy and SODA could I make that would be testable, preferably using simulated elections or mathematical demonstration/counterexamples? What voter model could capture enough of the sophisticated strategic thinking of which humans are capable? How about "SODA requires no self-reinforcing or defensive strategy"? These are honest, not rhetorical questions. I appreciate good responses, good research questions, from anyone, whatever you expect that the results of that research would be. Thanks, JQ
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