Policy and Practice Impacts

School Choice  Kidney Exchange  |  Cadet-Branch Matching


Policy and Practice Impacts on Cadet-Branch Matching

In a pair of papers Sönmez & Switzer (2013) and  Sönmez (2013),  I formulated a number of shortcomings of cadet-branch matching mechanisms at United States Military Academy (aka West Point) and ROTC respectively, and recommended an alternative mechanism, the Cadet-Optimal Stable Mechanism,  to escape these shortcomings. My proposed mechanism designs for this application built on the seminal paper entitled “Matching with Contracts” by Hatfield & Milgrom (2005)  along with an important generalization in Hatfield & Kojima (2010) . Immediately after my papers were published,  ROTC modified its mechanism mitigating (but not completely removing) some of these shortcomings.

2013 Reform in ROTC Cadet-Branch Matching Mechanism

One of the most important shortcomings of the ROTC cadet-branch matching mechanism is the adverse incentives it gives to a significant fraction of cadets to manipulate the system via “tanking” their efforts during their studies.  In May 2013,  the Army announced its plans to replace this mechanism in part due to the adverse “tanking” incentives harbored by their mechanism. Here is a link for the Army’s announcement.

2020 Reform in USMA & ROTC Cadet-Branch Matching Mechanisms

Since Fall 2019,  Parag Pathak and  I  have been collaborating with the officials at the U.S. Army Office of Economic and Manpower Analysis (OEMA) for a mechanism design that will best serve the Army’s objectives of talent alignment and retention. In February 2020, we have have signed a Memorandum of Understanding  with the OEMA leadership formalizing our collaboration. As a result of this partnership, both USMA and ROTC have adopted the Cadet-Optimal Stable mechanism starting with their October-2020 branching match, thus eliminating all shortcomings I formulated in Sönmez & Switzer (2013) and  Sönmez (2013). The new design also benefits from the slot-specific priorities introduced in Kominers and Sönmez (2016)

The role these shortcomings have played in 2020 reforms can be seen in the following Army announcement for their 2020 branching reform as well as in the following  video describing their new mechanism.