From electowiki
(Redirected from MATT)

"Maximum approval top-two" (or "MATT") is an approval-based primary election method that was proposed by User:RobLa, based on discussions that happened on the election-methods mailing list in 2018.[1][2] MATT uses the following steps:

  1. The candidate who receives the highest approval rating (the "front-runner") qualifies for the general election
    • Example: if there are 100 voters, and 40 approve of "A" and "B", 30 approve of only "B", and 30 approve of only "C", then "B" advances to the general election, since "B" is approved by 70% of voters.
  2. A second candidate (the "complementary candidate"), who maximizes the approval of the electorate, also qualifies (i.e. by having the highest approval among voters that did not approve of the front-runner). If two candidates both satisfy an equal part of the remaining electorate, the candidate with the highest overall approval rating advances.
    • Example: if there are 100 voters, and 40 approve of both "A" and "B", 30 approve of only "B", and 30 approve of only "C", then
      • "B" advances with 70% approval (per step 1)
      • "C" advances (per this step). "B" satisfies 70% of the electorate, and "C" satisfies the other 30%. So, 100% of the voters will be satisfied with one of their choices in the general election.


In 2018, User:RobLa led discussions about "MATT" and "MAF" on the election-methods mailing list.[1][2] They led to the creation of the "Maximum approval top-two" (or "User:RobLa/MATT") and the "Majority approval filter" (or "User:RobLa/MAF") pages here on electowiki.

  • "Maximum approval top-two" or "MATT" is an approval-based primary where voters use an approval voting ballot to select which candidates would be acceptable to advance to the general election. The maximum approval top-two method then selects no more than two candidates to advance to a general election.[3]
  • "Majority approval filter" or "MAF" is an approval-based primary election method that advances all candidates who are approved by a majority of the electorate, as well as often selecting one or more opposition candidates.

Neither MATT nor MAF took the world by storm. By 2019, User:RobLa was too concerned with his work at Internet Archive to promote either MATT or MAF, so it withered.

Meanwhile, the Center for Election Science helped the folks at STL Approves get off the ground in 2019. They were able to get St. Louis to switch to approval voting in the primary.[4] This method is called the "St. Louis method" as described on the "Approval-based primary election methods" page.


  1. a b Lanphier, Rob (2018-07-18). "[EM] A simpler approval based way of replacing the CA jungle primary". Retrieved 2021-02-06.
  2. a b Lanphier, Rob (2018-11-25). "Replacing the jungle primary". Medium. Retrieved 2021-02-06.
  3. User:RobLa and other editors (2018–2020). "Maximum approval top-two". Electowiki. Retrieved 2021-02-06.CS1 maint: uses authors parameter (link) CS1 maint: date format (link)
  4. Schlinkmann, Jesse Bogan, Mark. "The next mayor of St. Louis faces big challenges — and high expectations". Retrieved 2021-02-04.