NRMP Match Algorithm Explained: How Residency Matching Works

If an applicant does not match through the primary matching process, they must participate in SOAP (Specialized Open Access Program) to try to secure a position at a program with an open spot that also did not get matched. This process is described as the scariest thing that can happen to a human being in the medical residency context.

The NRMP uses an applicant-proposing algorithm that begins with a random applicant and attempts to match them to their first choice program, then second choice, and so on. Matches are tentative because applicants may be removed to make space for higher-ranked applicants. The algorithm will never penalize applicants for ranking reach programs, but ranking programs lower than true preference may prevent discovering if those programs would have been a match. SOAP (Supplemental Offer and Acceptance Program) helps fill unfilled positions after the main matching algorithm. It begins Monday of match week when unmatched applicants can apply to unfilled programs. SOAP consists of four offer rounds on Thursday, where programs make binding offers to applicants on their preference lists. Applicants receive offers and have 2 hours to accept or decline.

SOAP (Supplemental Offer and Acceptance Program) was created by the NRMP in 2012 to help unmatched programs fill positions with unmatched applicants. Every applicant should consider SOAP early, even if they don't want to, because failing to do so may prevent recognizing risk. Higher-risk categories include those with few interviews, red flags (failed USMLE/COMLEX, academic difficulties, negative MSPE comments, professionalism concerns, unexplained CV gaps), or those who had several interviews but not enough to feel comfortable. To be SOAP eligible, applicants must be registered for the main match, eligible to begin residency on July 1st, and be unmatched. A SOAP plan is a contingency plan for when you don't match. Critical mistakes to avoid include not updating personal information in ERAS, sharing unfilled program lists with others (violates NRMP rules), and contacting unfilled programs directly. On Monday at 11 AM Eastern, applicants access the unfilled programs list and can apply to 45 programs. At 3 PM, programs download applications and may conduct interviews. Programs create preference lists, and the NRMP extends offers during three offer rounds. After SOAP concludes, remaining positions become available, and applicants can contact programs freely. Positions open due to people dropping out or visa issues.

The Supplemental Offer and Acceptance Program (SOAP) is the process by which unmatched medical students attempt to secure residency positions after the initial match. On Tuesday of Match Week, programs begin reviewing applications and creating rank lists, while applicants hope for offers. By Thursday, applicants receive notifications about SOAP matches and have only two hours to accept or reject any offers. This process repeats throughout Thursday afternoon for unfilled positions. Accepting any offer is generally advisable since having a residency position—even in a less desirable program—is better than having none.

SOAP provides a uniform system for programs to offer unfilled positions after the initial algorithm run. During Match Week (March 16-20), unfilled positions are offered to eligible unmatched or partially matched applicants through a series of offer rounds. A partially matched applicant is someone who has matched to one type of position but not another—for example, someone who matched to a preliminary position but not an advanced position, or vice versa. Applicants can see all positions available in SOAP for a given application service, but the NRMP is the authoritative source for SOAP eligibility status.

The USMLE Couples Match is a specialized residency matching process where couples apply together through the NRMP (National Resident Matching Program) algorithm, which simultaneously matches both partners to programs where they can both be placed, requiring extensive communication, sacrifice, and strategic planning about priorities and compromises.

In the NRMP Match, couples can link their rank order lists to improve chances of matching together; the algorithm treats each pair of ranks as a unit and matches them at the highest acceptable ranked pair, with couples able to use 'No Match' codes and coordinate their lists through the R3 system while being aware of fees and certification requirements.

The NRMP (National Resident Matching Program) uses a sophisticated algorithm that simultaneously considers both candidate preferences and program preferences to create optimal matches; candidates rank programs in order of preference, and programs rank candidates, with the algorithm attempting to match each candidate to their highest possible choice while respecting program preferences. For couples, both partners must apply to programs in the same geographic location and include coordinated options in their preference lists to maximize the chance of both matching in the same area. SOAP (Supplemental Offer and Acceptance Program) allows unmatched candidates to apply for remaining positions after the initial match, typically starting on Tuesday of Match Week, providing an additional opportunity for candidates who did not match in the initial process.

Couples matching in US residency allows medical couples to coordinate their applications through the NRMP, enabling them to rank programs together and increase the likelihood of matching in the same geographic area; while this process doesn't inherently reduce individual matching chances if both partners have strong credentials and interview well, it requires careful coordination, similar CVs, proactive communication with programs, and willingness to consider various combination scenarios to maximize success.

Couples match is a residency matching process where two individuals apply separately through RAS but link applications through NRMP. Partners designate they want to couple, select each other, and the algorithm attempts to match both into compatible programs. The primary goal is geographic proximity for couples in committed relationships. Key logistics include: fees are per partner based on rank order list length, partners can see each other's rank lists but not modify them, couples can use no-match codes, and uncoupling is allowed before rank order certification. The algorithm only processes couples as a unit once designated.

Market design involves creating systems where efficient outcomes result. Matching markets differ from commodity markets because both parties must be chosen by each other—you can't just choose what you want even if you can afford it. Marketplaces must solve three problems: making the market thick (enough participants), dealing with congestion (too many potential transactions), and ensuring safety (protecting participants and enabling information revelation). A transaction is 'repugnant' if some people want to engage in it while others believe it shouldn't be allowed, like kidney exchange which is illegal in the US. The medical residency market evolved from early hiring two years before graduation (inefficient) to a centralized clearinghouse in the 1950s where doctors and hospitals submit rank-order lists. As women entered medical schools and couples began applying, the system required redesign to place both spouses in the same region.

The medical residency market evolved from unregulated competition with exploding offers to a centralized clearinghouse. Before 1945, hospitals made early offers, causing information loss and rushed decisions. Centralized clearinghouses solved unraveling by producing stable matchings where no doctor-hospital pair prefers each other over current assignments. This demonstrates how market design addresses coordination failures in large, complex matching markets.

This extensive section establishes the theoretical and practical foundations of market design. It distinguishes matching markets (requiring mutual selection) from commodity markets (price-based allocation), explaining why traditional economics fails in contexts like college admissions, labor markets, and organ transplantation. The lecture introduces three essential marketplace functions: creating thickness, managing congestion, and ensuring safety. Through detailed case studies—including the American medical residency matching system and Boston school choice—the section demonstrates how centralized clearing houses solve allocation problems by preventing strategic manipulation and achieving Pareto improvements. The kidney exchange narrative illustrates how paired donation and non-directed donor chains overcome compatibility constraints, while contrasting U.S. and German legal frameworks shows how regulatory differences dramatically affect outcomes. Throughout, the narrative emphasizes that effective market design requires understanding both theoretical mechanisms and real-world behavioral constraints.

A landmark antitrust lawsuit against the National Association of Realtors has resulted in a $418 million fine and mandated changes to how agents sell real estate and get paid. The lawsuit addresses three ways agents have ruined the market: making it not worth selling, creating steering problems through commission splits, and enabling private deals that undermine competition. The MLS system allowed agents to advertise commission splits to buyer agents, creating incentives to push properties regardless of quality. This has contributed to real estate price growth by making legitimate price discovery difficult, as both sides want sales at any price.