This page allows you to instantly compute approvalbased committee voting rules online, including PAV (Proportional Approval Voting), Phragmén's methods, and the Method of Equal Shares. 27 voting rules are available. The computations are done locally in your browser. You can also generate random profiles. By clicking on a selected committee, you can check the axiomatic properties of the committee and the algorithm's steps for finding it. ✗
Configure Random Profile Generator
For more information, see the prefsampling package.

alpha : float in [0, ∞)  After sampling a ranking, alpha * m! copies are added to the urn, where m is the number of candidates. A value of 0 corresponds to Impartial Culture. A value of 1.0 means that in the second iteration, there is a chance of 0.5 that the ballot of the first iteration is chosen and a chance of 0.5 that a new ballot is drawn according to Impartial Culture.

phi : float in [0, 1]  dispersion parameter of the Mallows model where phi = 1 leads to Impartial Culture and phi = 0 leads to every voter having the same ranking.normalise_phi : bool  whether to normalize the phi parameter as as discussed in Boehmer, Faliszewski and Kraiczy (2023).

dimension : int  dimension of the Euclidean spacespace : str  probability distribution of the voter and candidate points

alphas : list of floats  Commaseparated list indicating for each alternative how many "balls" to place in the urn  rankings will be produced by sequentially drawing balls from the urn without replacement.

alphas : list of floats  The Direct Dirichlet model is very similar to the PlackettLuce model, but the quality of the candidates is drawn from a Dirichlet distribution. The key difference is that the higher the sum of the alphas, the more correlated the votes are (the more concentrated the Dirichlet distribution is).
Properties:
Tied winning committees: (can be slow)
Preflib .soc:
Preflib .toc:
Abif:
JSON:
CSV:
Select voting rules to compute
Library of interesting example profiles
 PAV compared to Phragménstyle rules (shown at startup) Peters and Skowron, 2020, "Proportionality and the Limits of Welfarism", Introduction
 Running example used by Lackner and Skowron (2023) Lackner and Skowron, 2023, "MultiWinner Voting with Approval Preferences", Springer, Example 2.1
 PAV fails core Aziz et al, 2016, "Justified Representation in ApprovalBased Committee Voting", Example 6
 SeqPAV fails JR (minimal example, k = 6, 108 voters) SánchezFernández et al, 2016, "Proportional Justified Representation", Table 2
 SeqPhragmén fails EJR Brill et al, 2021, "Phragmen's Voting Methods and Justified Representation", Example 6
 leximax and varphragmen fail EJR Brill et al, 2021, "Phragmen's Voting Methods and Justified Representation", Example 5
 RevSeqPAV fails JR Aziz, 2017, "A Note on Justified Representation Under the Reverse Sequential PAV rule", Proposition 2 for k = 5
 SeqPhragmén/seqPAV/Equal Shares fail Pareto optimality Lackner and Skowron, 2020, "Utilitarian welfare and representation guarantees of approvalbased multiwinner rules", Example 2
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 preflib .soc
 .abif
 .json
 .csv