This investigation into classroom interaction uses survey data to asse
ss why students offer comments or raise questions in class. Previous r
esearch assumed that instructors shape students' involvement. In this
report, classes are recognized as groups able to influence students' p
articipation. I investigate how class traits (e.g, interaction norms,
emotional climate) and students' traits (e.g., comprehension, confiden
ce) may encourage participation. Multiple regression analyses of profe
ssors responses suggest that class interaction norms, students' prepar
ation, and student-to-student interactions significantly shape class i
nvolvement. In contrast, students' responses highlight their confidenc
e and its effect on class participation. The data suggest that faculty
members may play a much less direct role in classroom interaction tha
n has previously been assumed.