Kingmaker

Kingmaker is a modular, performant, social choice framework for the simulation, computation, and analysis of strategic voting. It has a focus on the study of strategic or tactical voting, which is concerned with questions such as:

1. Which strategies are most effective (for a given voting method)?
2. To what degree do strategies impact the outcome of elections?
3. Which voting methods minimize strategic voting?

and much more.

Getting Started

To get started with Kingmaker, just configure the election parameters and run the simulation. Here's an example:

use kingmaker::prelude::*;

fn main() {
    // configure election
    let candidates = [
        Candidate::new(0, "Alice", Some("DEM"), Default::default()),
        Candidate::new(1, "Bliar", Some("REP"), Default::default()),
        Candidate::new(2, "Cybil", None, Default::default()),
    ];
    let voting_blocks = [
        VotingBloc::builder(preferences::Mallows::new(vec![0, 2, 1], 1.4), 40)
            .add_tactic(tactics::Burial::new(vec![1]), 0.8) // Do not vote for the opposition!
            .add_tactic(tactics::Identity, 0.2)
            .build(),
        VotingBloc::builder(preferences::Mallows::new(vec![1, 2, 0], 1.0), 45)
            .add_tactic(tactics::Burial::new(vec![0]), 0.8) // Do not vote for the opposition!
            .add_tactic(tactics::Identity, 0.2)
            .build(),
        VotingBloc::builder(preferences::Mallows::new(vec![2, 0, 1], 1.2), 15)
            .add_tactic(tactics::Identity, 0.8)
            .add_tactic(tactics::Compromise::new(vec![0]), 0.2) // Compromise for A (DEM) instead
            .build(),
    ];
    let election = Election::new(candidates, voting_blocks, methods::IRV);
    // run election
    let outcomes = election.run_many(1_000, 0);
    election.display(&outcomes);
}

Acknowledgments

• Much thanks to the folks at pref_voting for their comprehensive work on social choice research.
• I'd also like to thank my advisor Michael Pearce for his guidance and support.