Algorithm & Rankings

Algorithm & Rankings

How the Algorithm Works

  • How does the Match algorithm work?

    The matching algorithm uses 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 for each participant.

    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.

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 programs at the residency sites to which you applied that would be acceptable to you. Do not rank any program that you would not want to be matched to 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 yourself. For example, if you decide to order your preferences by how likely you think it will be to get into a program, you may not get the best result.

Submit Rankings

  • How do I submit and certify my Rank Order List?

    Applicants must submit and certify their Rank Order List online in the NMS Match System by the Rank Order List deadline. The Rankings User Guide includes information on how to:

    • Add a program to your Rank Order List
    • Delete a program from your Rank Order List
    • Reorder a program on your Rank Order List
    • Certify your Rank Order List
    • Print your Rank Order List
    Related Links:
  • Can I rank a residency site where I didn't apply or receive an interview?

    Yes, although it is highly unlikely that you will match to that residency site. Residency sites typically review applications, interview, and evaluate applicants to determine who they are willing to accept into the residency site. If you did not apply or interview with a residency site, it is unlikely the residency site is considering you for a position. If you are not ranked by a residency site, you cannot match to that residency site.

  • What should I do if the program I want to rank is withdrawn?

    You should leave the withdrawn program ranked on your list. If you leave the program on your list and the program's participation status in the Match becomes Active before the Rank Order List deadline, that ranking will be used in the Match. If the program remains withdrawn, that ranking will not be used in the Match, and your list will be processed as if you had not ranked the withdrawn program.

  • I can't find the program I want to rank in the NMS Match System.

    Only programs that are registered for the Match may be included on your Rank Order List. Consult the List of Participating Programs to ensure the program you want to rank is being offered in the Match.

    If the program is not included in the List of Participating Programs, contact the Program Director directly to clarify the program's status in the Match.

    Within the NMS Match System, programs can be searched by Code Number, name of residency site, location, program description, Program Director name, or program Code Number as they appear in the List of Participating Programs.

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