Algorithm & Rankings

Algorithm & Rankings

How the Algorithm Works

  • How does the Match algorithm work?

    The matching algorithm uses the preferences stated on the applicant Rank Order Lists, the program Rank Order Lists, and the number of available positions at each program to find the best possible outcome.

    The algorithm starts with an attempt to place an applicant into the program that is most preferred on the applicant's list. Each applicant's Rank Order List is traversed "downwards", from most preferred program to least preferred, until the first program is reached at which the applicant can be tentatively matched, or until the applicant's list of choices is exhausted. Each program accepts applicants "upwards" on its Rank Order List, continually removing less preferred matches in favor of more preferred applicants, until the program is matched to the most preferred applicants who wish to be matched to the program.

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Ranking Strategy

  • What is the best strategy for ranking?

    In order to get your best possible result, you should rank your choices in order of your true preferences. Rank all applicants that you would be willing to accept. Do not rank any applicant that you would not want to be matched to your program under any circumstances.

    The algorithm is specifically designed to give each participant their best result if they rank their choices in order of true preference. Using any other strategy may cause you to get a worse result for your program. For example, if you decide to order your preferences by how highly you think an applicant will rank your program, you may not get the best possible result for your program.

Submit Rankings

  • What should I do if an applicant appears on my Rank Order List as "Withdrawn"?

    Withdrawn applicants may change their status and decide to participate in the APPCN Match at any time until the Rank Order List deadline. Therefore, if you planned to rank an applicant who is shown as withdrawn, you are strongly encouraged to leave the withdrawn applicant on the Rank Order List.

    If you leave the withdrawn applicant on the list and the applicant is reinstated prior to the deadline, that ranking will be used in the matching process. If the applicant remains withdrawn, that ranking will not be used in the matching process, and the Rank Order List will be processed as if you had not ranked the withdrawn applicant.

    If you have any questions concerning the status of an applicant in the APPCN Match, you should contact the applicant directly.

Special Requirements

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