How does NRMP Match algorithm work?

The NRMP matching algorithm for USMLE residency (and fellowship) match is based on a Nobel Prize winning matching making program. It is one of the most advanced matching systems currently in the world.
We will try to explain it in the simplest way possible.
Before we do that, here are some useful tips

Tip 1: You need to certify your Rank Order List (ROL) any time before the deadline. As long as you meet the deadline, it does not impact where (or if) you will match.

Tip 2: The programs and the applicants have the same deadline for certifying their ROL, but most programs
Now lets get back to the NRMP match algorithm.

Assume that there are four applicants: applicant 1, Applicant 2 and Applicant 3 and Applicant 4 and there are 4 programs: Program A, Program B and Program C
All four applicants interviewed in all three programs and this is how the applicants ranked the programs respectively
  • Applicant 1: Program A, Program B and program C (in that order)
  • Applicant 2: Program A, Program B and program C (in that order)
  • applicant 3: Program B, Program A and program C (in that order)
  • applicant 4: Program B, Program A and program C (in that order)
 
Now let’s see how the programs ranked the Applicants.
  • Program A, Applicant 1, Applicant 2 , Applicant 4, did not rank applicant 3
  • Program B, Applicant 2, Applicant 1, Applicant 4 , Applicant 3
  • Program C, Applicant 1, Applicant 4, Applicant 3 , Applicant 2

Tip 3: Match algorithm favors the applicant.
since the system is made in a way it favors the Applicants over the program the matching is run from the applicant’s side.

Let’s look at Applicant 1, who put program A as top choice, Program A also put him/her in its top choice, so applicant A matches into program A.  The cycle closes for applicant A and applicant A got program A his/her top choice – Matched!

Now let’s look at applicant 2: He/she also put residency program A as his/her top choice, but the program ranked him/her second. As long as program A has 2 or more spots, applicant 2 also matches there- Since the match system favours the applicant. Applicant 2 also got his/her first choice! Matched!

Now let’s see Applicant 3: He/she put program B as his top choice, he/she is provisionally matched into program B, since there are other applicants that the Program B has ranked and the algorithm must place them first. So 3 is not matched yet.

Now let’s look at Applicant 4, who also put Program B as his/her top choice and matches there but matches at a higher rank than applicant 3. Now if the program had just three slots then Applicant 3 now will have to match somewhere else.  Applicant 4 matches into Program B and Applicant 3 is displaced out!

​The system then runs applicant 3 second choice. In this case applicant 3 second choice is program A but since he isn’t ranked there by the program, the algorithm matches applicant 3 to his/her lowest program choice Program C.  Applicant 3 matched into his/her 3rd choice but nevertheless he has Matched.

What happens if Program 3 had not ranked applicant 3?

In this case the program 3 will have vacant spots since Applicants 1, 4 and 2 which it ranked already matched at other programs. So the program can go into SOAP to fill the vacant spots.
Similarly, in this case, applicant 3 will not match in the main NRMP cycle and will need to go into SOAP.

Hopefully this article helps you understand the NRMP match process better.

​So to reiterate:
  • Since the match favors the applicants, it your responsibility to rank the programs you want to match into higher than others
  • If a program has ranked you (to match), you are bound to match in the program unless you match higher.
Watch our videos below to get more insights into how you make your rank order list and what programs consider while ranking.

Useful Videos for IMGs

How will programs rank you? Discussion with a former Program coordinator
Second visit to residency programs
How to prepare your rank order list