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.
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 to which you applied that would be acceptable. Do not rank any program that you would not want to be matched to, even if it was the only position available to you in the Match.
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. If you decide to order your preferences in another way (e.g., by how likely you think it will be to get into the program), you may not get the best possible result.
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:
- Importing rankings from your applications
- 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
Can I rank a program where I didn't apply or receive an interview?
Yes, although it is highly unlikely that you will match to that program. Programs typically review applications, interview, and evaluate applicants to determine who they are willing to accept into the program. If you did not apply or interview with a program, it is unlikely the program is considering you for a position. If you are not ranked by a program, you cannot match to that program.
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 ORMatch 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.
Can I change my rankings after certifying my list?
Yes. You can make changes to a Rank Order List that has been certified at any time prior to the Rank Order List deadline.
If you make changes to a list after it has been certified, you simply have to certify the list again before the deadline in order for it to be used in the Match.
Can I view my Rank Order List after the deadline?
Yes. You will be able to view your Rank Order List until 4 days after the release of the Match results. However, you will not be able to change any information or certify a Rank Order List in the NMS Match System after the Rank Order List deadline.Related Links: