National Resident Matching Program
Encyclopedia
The National Resident Matching Program (NRMP) (or the Match) is a United States
-based non-profit non-governmental organization
created in 1952 to help match medical school
students with residency
programs. The NRMP is sponsored by the American Board of Medical Specialties
(ABMS), the American Medical Association
(AMA), the Association of American Medical Colleges
(AAMC), the American Hospital Association
(AHA), and the Council of Medical Specialty Societies (CMSS).
After its institution in 1952, the NRMP algorithm saw only minor and incremental changes until 1995, when controversy arose regarding whether the program was susceptible to manipulation or unreasonably fair to employers. Indeed, it was shown that in simple cases (i.e. those that exclude couples, second-year programs, and special cases for handling unfilled slots) that had multiple "stable" matchings, the algorithm would return the solution that was best for the hospitals and worst for the applicants. It was also susceptible to collusion on the part of hospitals: if hospitals were to organize their preference lists properly, the result returned would be completely unaffected of the preference lists of the residents. As a result, "in the fall of 1995 the Board of Directors of the NRMP comissioned the design of a new algorithm for conducting the match [that would be as favorable as possible to the applicants], and a study comparing it to the existing NRMP algorithm." The new algorithm was adopted in May 1997 and has been in use since its first application in March 1998, although the study showed that the effects of the change on actual matches was minimal.
, and as a result the solutions to the two problems are very similar. A simplified version of the algorithm that is used to perform the match is described on the NRMP website. However, this description does not describe the handling of couples (pairs of applicants who wish to stay in the same geographic location), second-year positions, or special handling of residency positions that remain unfilled. The full algorithm is described in
As in the stable marriage problem
, the basic goal in the simple case of the hospitals/residents problem is to match applicants to hospitals so that the final result is "stable". "Stability" in this case means that there is no applicant A and hospital H such that both of the following are true:
It can be shown that for any instance of the problem, there is at least one valid solution. Under the old (pre-1995) NRMP algorithm, which favored hospitals over residents, in certain cases hospitals could benefit from lying about their preferences, but that is no longer true under the new system. In neither system can a resident or coalition of residents benefit simply by lying about their preferences, even if they have perfect knowledge of everyone's preferences. (Of course, both systems are susceptible to other forms of collusion. For example, if two applicants apply to the same program, the weaker is still capable of bribing the stronger into ranking the program lower on his list than he would otherwise.)
Under the current system, it is impossible for an applicant to be harmed by including more residency programs at the bottom of his list if those programs are indeed preferable to not being matched.
. As a result, the algorithm used by the NRMP is not strictly guaranteed to return a result in a reasonable amount of time, even if one exists. Also, while there is no randomization in the NRMP algorithm—so it will always return the same output when given exactly the same input-- different outcomes can be produced by changing trivial features of the data such as the order in which applicants and programs are processed. However in initial testing of the algorithm over 5 years of residency match data and a variety of different initial conditions, the current NRMP algorithm always terminated quickly on a stable solution. Testing also showed that "none of [the trivial] sequencing decisions had a large or systematic effect on the matching produced"--the maximum number of applicants ever observed to be affected in a single run was 12 out of 22,938.
In general once the hospitals' preference lists have been set, there is no way for an applicant to match into a better position by deciding to match in a couple. For example, if a very strong applicant and a very weak applicant match as a couple, there is no mechanism in the algorithm that allows the stronger applicant to somehow improve the desirability of the weaker applicant. (Of course, if the hospitals know that the stronger and weaker applicant are matching together prior to the run of the algorithm, they are always free to change their preference lists accordingly, which will obviously affect the final outcome.) Ensuring the members of the couple end up in compatible programs is essentially achieved by matching them individually and having them turn down programs, moving on to less desirable ones until their positions are acceptable, though the algorithm does not function exactly in this way. As a result, all else being equal, couples are relatively likely to be matched with less desirable programs than they would have been had they decided to match individually.
However, it is not impossible for couples to match into better positions than they would have individually. First, since the algorithm does depend on some arbitrary factors (e.g. the order in which applicants are processed), one or both of the individuals could end up in a better position by chance alone, although this is extremely unlikely. Second, anything that affects the hospitals' preference lists prior to the run of the algorithm will obviously affect the final outcome, as in the case with the strong and weak applicant above. There is also some belief that being a part of a couple may be appealing in and of itself.
is required to have an ECFMG certification by the "rank order list certification deadline" time (usually in February of the year of the match).
To acquire an ECFMG certification, the main requirements are:
In comparison, regular graduates from medical schools in the United States need to complete USMLE Steps 1 and 2 as well, but can participate in the NRMP while still doing their final year of medical school before acquiring their medical diplomas. In effect, taking regular administrative delays into account, and with residency programs starting around July, there is a gap of at least half a year for IMGs between graduation from medical school and beginning of a residency program, in contrast to US graduates who may start residency directly after completing medical school.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
-based non-profit non-governmental organization
Non-governmental organization
A non-governmental organization is a legally constituted organization created by natural or legal persons that operates independently from any government. The term originated from the United Nations , and is normally used to refer to organizations that do not form part of the government and are...
created in 1952 to help match medical school
Medical education in the United States
Medical education in the United States includes educational activities involved in the education and training of medical doctors in the United States, from entry-level training through to continuing education of qualified specialists....
students with residency
Residency (medicine)
Residency is a stage of graduate medical training. A resident physician or resident is a person who has received a medical degree , Podiatric degree , Dental Degree and who practices...
programs. The NRMP is sponsored by the American Board of Medical Specialties
American Board of Medical Specialties
The American Board of Medical Specialties is a non-profit physician-led umbrella organization for 24 of the 26 approved medical specialty boards in the United States...
(ABMS), the American Medical Association
American Medical Association
The American Medical Association , founded in 1847 and incorporated in 1897, is the largest association of medical doctors and medical students in the United States.-Scope and operations:...
(AMA), the Association of American Medical Colleges
Association of American Medical Colleges
The Association of American Medical Colleges is a non-profit organization based in Washington, DC and established in 1876. It administers the Medical College Admission Test...
(AAMC), the American Hospital Association
American Hospital Association
The American Hospital Association is an organization that promotes the quality provision of health care by hospitals and health care networks through such efforts as promoting effective public policy and providing information related to health care and health administration to health care...
(AHA), and the Council of Medical Specialty Societies (CMSS).
History
The National Resident Match Program began in 1952 in response to dissatisfaction with the process and results of matching applicants to residency programs via the decentralized, competitive market. From shortly after the first residency programs were formally introduced, the hiring process was "characterized by intense competition among hospitals for (an inadequate supply) of interns." In general, hospitals benefited from filling their positions as early as possible, and applicants benefited from delaying acceptance of positions. The combination of these factors lead to offers being made for positions up to two years in advance. While efforts made to delay the start of the application process were somewhat effective, they ultimately resulted in very short deadlines for responses by applicants, and the opportunities for dissatisfaction on the part of both applicants and hospitals remained.After its institution in 1952, the NRMP algorithm saw only minor and incremental changes until 1995, when controversy arose regarding whether the program was susceptible to manipulation or unreasonably fair to employers. Indeed, it was shown that in simple cases (i.e. those that exclude couples, second-year programs, and special cases for handling unfilled slots) that had multiple "stable" matchings, the algorithm would return the solution that was best for the hospitals and worst for the applicants. It was also susceptible to collusion on the part of hospitals: if hospitals were to organize their preference lists properly, the result returned would be completely unaffected of the preference lists of the residents. As a result, "in the fall of 1995 the Board of Directors of the NRMP comissioned the design of a new algorithm for conducting the match [that would be as favorable as possible to the applicants], and a study comparing it to the existing NRMP algorithm." The new algorithm was adopted in May 1997 and has been in use since its first application in March 1998, although the study showed that the effects of the change on actual matches was minimal.
Matching Algorithm
The problem of matching hospitals to residents is a generalization of the stable marriage problemStable marriage problem
In mathematics and computer science, the stable marriage problem is the problem of finding a stable matching between two sets of elements given a set of preferences for each element. A matching is a mapping from the elements of one set to the elements of the other set...
, and as a result the solutions to the two problems are very similar. A simplified version of the algorithm that is used to perform the match is described on the NRMP website. However, this description does not describe the handling of couples (pairs of applicants who wish to stay in the same geographic location), second-year positions, or special handling of residency positions that remain unfilled. The full algorithm is described in
Inputs
Senior medical students usually begin the application process at the beginning of their (usually) fourth and final year in medical school. After they apply to programs, programs review applications and invite selected candidates for interviews held between October and February. After the interview period is over, the applicants and programs each compile "rank-ordered lists". For programs, this is a list of applicants in order from most to least preferable. Similarly, for residents not matching in couple, the rank-ordered list is a list of programs in order from most to least preferable. For couples, the rank-ordered list is a list of pairs of schools (or a single school and "No match"). In some cases, applicants may also submit secondary lists to simultaneously apply for programs that begin in the second year of residency.Simple Case: No couples or Secondary Programs
In order to understand how the current NRMP algorithm works, it is helpful to begin by considering the simpler case where there are no couples or secondary programs.As in the stable marriage problem
Stable marriage problem
In mathematics and computer science, the stable marriage problem is the problem of finding a stable matching between two sets of elements given a set of preferences for each element. A matching is a mapping from the elements of one set to the elements of the other set...
, the basic goal in the simple case of the hospitals/residents problem is to match applicants to hospitals so that the final result is "stable". "Stability" in this case means that there is no applicant A and hospital H such that both of the following are true:
- A is unmatched or would prefer to go to H over the hospital he is currently matched with
- H has a free slot or would prefer A over one of the candidates currently filling one of its slots.
It can be shown that for any instance of the problem, there is at least one valid solution. Under the old (pre-1995) NRMP algorithm, which favored hospitals over residents, in certain cases hospitals could benefit from lying about their preferences, but that is no longer true under the new system. In neither system can a resident or coalition of residents benefit simply by lying about their preferences, even if they have perfect knowledge of everyone's preferences. (Of course, both systems are susceptible to other forms of collusion. For example, if two applicants apply to the same program, the weaker is still capable of bribing the stronger into ranking the program lower on his list than he would otherwise.)
Under the current system, it is impossible for an applicant to be harmed by including more residency programs at the bottom of his list if those programs are indeed preferable to not being matched.
Couples
Adding couples who submit joint preference lists complicates the problem significantly. In some cases there exists no stable solution (with stable defined similarly to the way it is in the simple case). In fact, the problem of determining whether there is a stable solution and finding it if it exists has been proven NP-completeNP-complete
In computational complexity theory, the complexity class NP-complete is a class of decision problems. A decision problem L is NP-complete if it is in the set of NP problems so that any given solution to the decision problem can be verified in polynomial time, and also in the set of NP-hard...
. As a result, the algorithm used by the NRMP is not strictly guaranteed to return a result in a reasonable amount of time, even if one exists. Also, while there is no randomization in the NRMP algorithm—so it will always return the same output when given exactly the same input-- different outcomes can be produced by changing trivial features of the data such as the order in which applicants and programs are processed. However in initial testing of the algorithm over 5 years of residency match data and a variety of different initial conditions, the current NRMP algorithm always terminated quickly on a stable solution. Testing also showed that "none of [the trivial] sequencing decisions had a large or systematic effect on the matching produced"--the maximum number of applicants ever observed to be affected in a single run was 12 out of 22,938.
In general once the hospitals' preference lists have been set, there is no way for an applicant to match into a better position by deciding to match in a couple. For example, if a very strong applicant and a very weak applicant match as a couple, there is no mechanism in the algorithm that allows the stronger applicant to somehow improve the desirability of the weaker applicant. (Of course, if the hospitals know that the stronger and weaker applicant are matching together prior to the run of the algorithm, they are always free to change their preference lists accordingly, which will obviously affect the final outcome.) Ensuring the members of the couple end up in compatible programs is essentially achieved by matching them individually and having them turn down programs, moving on to less desirable ones until their positions are acceptable, though the algorithm does not function exactly in this way. As a result, all else being equal, couples are relatively likely to be matched with less desirable programs than they would have been had they decided to match individually.
However, it is not impossible for couples to match into better positions than they would have individually. First, since the algorithm does depend on some arbitrary factors (e.g. the order in which applicants are processed), one or both of the individuals could end up in a better position by chance alone, although this is extremely unlikely. Second, anything that affects the hospitals' preference lists prior to the run of the algorithm will obviously affect the final outcome, as in the case with the strong and weak applicant above. There is also some belief that being a part of a couple may be appealing in and of itself.
International medical graduates
To participate in the NRMP, an international medical graduateInternational medical graduate
An International Medical Graduate or "IMGs", earlier known as a Foreign Medical Graduate or "FMGs", is a term used to describe a physician who has graduated from a medical school outside of the country in which he or she intends to practice...
is required to have an ECFMG certification by the "rank order list certification deadline" time (usually in February of the year of the match).
To acquire an ECFMG certification, the main requirements are:
- Completion of USMLE Step 1USMLE Step 1The USMLE Step 1 is the first part of the United States Medical Licensing Examination. It assesses whether medical school students or graduates can apply important concepts of the sciences fundamental to the practice of medicine. US medical students typically take Step 1 at the end of the second...
, USMLE Step 2 Clinical Knowledge and USMLE Step 2 Clinical Skills - A medical diploma of medical educationMedical educationMedical education is education related to the practice of being a medical practitioner, either the initial training to become a doctor or additional training thereafter ....
taken at a institution registered in the International Medical Education DirectoryInternational Medical Education DirectoryThe International Medical Education Directory is a public database of worldwide medical schools. The IMED is published as a joint collaboration of the Educational Commission for Foreign Medical Graduates and the Foundation for Advancement of International Medical Education and Research...
(IMED)
In comparison, regular graduates from medical schools in the United States need to complete USMLE Steps 1 and 2 as well, but can participate in the NRMP while still doing their final year of medical school before acquiring their medical diplomas. In effect, taking regular administrative delays into account, and with residency programs starting around July, there is a gap of at least half a year for IMGs between graduation from medical school and beginning of a residency program, in contrast to US graduates who may start residency directly after completing medical school.