A university implements a voluntary first-year tutoring prog…
A university implements a voluntary first-year tutoring program. End-of-year analysis shows tutoring participants (participants=127) have higher GPAs than non-participants (participants = 200). The president recommends expansion across the institution. Further analysis reveals: Tutoring participants had higher high school GPAs (3.61 vs. 3.35) before college Participation was entirely voluntary; self-selection likely indicates higher motivation Tutoring participants also attended office hours (68% vs. 42%) and study groups (71% vs. 34%) more frequently First-generation students participated at lower rates (12% of tutoring participants vs. 31% of non-participants) despite identical initial college GPAs Students who participated in tutoring also had higher rates of advisor contact and academic planning discussions The most serious threat to concluding that tutoring caused the GPA difference is: