One, although not the only, segment of the supply pipeline at which interventions to increase the size of the Science, Technology, Engineering and Mathematics (STEM) workforce in the U.S. are targeted involves the number of U.S. students who receive STEM degrees. Many of these interventions are aimed at influencing college enrollment behavior. However, low overall persistence rates combined with low rates of retention in STEM majors among those who do graduate highlight the importance of interventions to promote the success of undergraduate STEM students.

Although a variety of such interventions have been proposed and implemented, evidence regarding their effectiveness is sparse. Our paper reports on a randomized control trial of four interventions intended to support the success of freshman STEM students conducted at the University of Maryland, Baltimore County. A total of 1260 freshmen who entered the university in the fall 2011, fall 2012 or fall 2013 semesters and intended to major in a STEM field participated in this project. The interventions tested include:

• assistance in forming and maintaining study groups;
• mentoring provided by high-status faculty in the student’s intended major;
• mentoring provided by an experienced staff member; and
• placement in an active learning discussion section of a foundational math (pre-calculus or calculus) class.

We discuss challenges faced in the random assignment process and how they were addressed and describe the interventions that were implemented. In addition, intent-to-treat as well as the effect of treatment-on-the-treated estimates of the impact of the interventions on retention at the university, retention in a STEM major, overall grades and grades in STEM courses based on data from the 2011-12, 2012-13 and 2013-14 academic years are presented.