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.Related Links:
Is there a video explaining the Match Process?
Yes, a video, examples, and an interactive demonstration are available on the Matching Algorithm page.Related Links:
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 where you applied that would be acceptable. 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.
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
Do my rankings from Phase I affect my rankings in Phase II?
No. If you do not obtain a position in Phase I of the Match, you will submit a new Rank Order List for Phase II of the Match.
The Rank Order List you submit for Phase II is completely unrelated to the Rank Order List you submitted for Phase I. None of the rankings you submitted for Phase I will be carried over to Phase II. You may apply to and rank any program that is participating in Phase II on your Phase II Rank Order List.
If you discover that a program to which you previously applied in Phase I has a position available in Phase II, you may apply to that program again for Phase II, and rank that program on your Rank Order List for Phase II if you wish (whether or not you included that program on your Rank Order List for Phase I).
What should I do if I do not want to submit a Rank Order List?
If you have accepted a position at an internship that is not participating in the Match, or if you decide not to submit a Rank Order List for any other reason, you should withdraw from the Match.
In the NMS Match System, you can select whether you want to withdraw only from Phase I of the Match, or both Phase I and Phase II of the Match.
If you withdraw from the Match and then subsequently decide that you want to participate, you can use the NMS Match System to reinstate yourself in the Match prior to the Rank Order List deadline for each Phase of the Match.Related Links:
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 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 Internships to ensure the program you want to rank is registered for the Match.
If the program is not included in the List of Participating Internships, contact the Training Director directly to clarify the program's participation status in the Match.
Within the NMS Match System, programs can be searched by Match Code Number, name of training site, location, program description, or name of the Training Director, as they appear in the List of Participating Internships. AAPI and/or the APPIC Directory may have different names for programs than the NMS Match System, so be sure to search for programs using the information shown in the List of Participating Internships on this website.Related Links:
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.Related Links:
Can I view my Rank Order List after the deadline?
Yes. You will be able to view and print your Rank Order List for either Phase of the Match for 3 days after the release of the Match results for that Phase of the Match. 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: