This article integrates a series of studies conducted over a 15-year period in a multi-section educational course taught by the same supervising professor and his GTAs . The purpose of each study was to determine whether particular interventions or student characteristics affected performance levels in the course. Over the extended period of research, approximately 6000 undergraduate students, with 25 to 55 students in each of more than 200 sections, participated in a variety of research projects related to student performance in the course. The principal research themes addressed were (1) critical thinking, (2) additional cognitive measures (e.g., initial course knowledge, generic vocabulary), (3) class participation, (4) in-class writing activities, and (5) cooperative learning.