Jameson Quinn, a Harvard stats PhD who also formerly served with myself and Warren on the board of the Center for Election Science, conducted computer simulations showing that STAR voting generally performs a bit better than score voting.
Is it enough of an improvement to justify the added complexity of the runoff? I’m not sure. But I have noticed that the runoff step seems useful as a marketing device when talking to proponents of methods like Instant Runoff Voting, who intuitively worry about strategy with score voting. I’ve been one of the world’s leading advocates of score voting since 2006, and I’ve heard the strategy arguments hundreds or thousands of times. I grow tired of having to re-explain the counterintuitive game theory. STAR voting seems to generally allay these concerns, whether justifiably or not. It has rapidly built a movement that score voting was never able to achieve. It’s as if the added complexity works as an effective gimmick. I digress. I’ll take either.