The Impact of Semester Gaps on Student Grades

College students have great flexibility in choosing when they take specific courses. These choices sometimes are constrained by prerequisite requirements, which determines the order in which pairs of courses may be taken. However, even in these cases the student can choose the number of semesters, or gap, between the pairs of courses. In this paper we study the impact that this gap has on student learning, as measured by course grades. Our methodology accounts for differences in instructor grading policies and in student ability as measured by overall grade point average. Our results can be used to inform course selection and advising strategies. Our study is applied to eight years of undergraduate course data that spans all departments in a large university. Due to space limitations, in this paper we focus our analysis on the semester gaps in Computer Science courses and in Spanish courses. Our results do not show a consistent negative impact on increasing semester gaps between all pairs of courses in a department; however, a negative impact is shown when the gap increases between courses that have a particularly strong relationship and overlapping content.