"It's very clear to me that students are much less threatened by TFs than by me," she says.

TFs express a range of views on their role as teachers. Maria K. Blees '97, a former CS-50 TF, says she sees herself as more of a facilitator than a primary instructor.

But "in Ec 10 most of the primary instruction is done by TFs," says Felix S. Lee, a TF for Social Analysis 10: "Principles of Economics" and a third-year law student.

And Susan E. Spinale, a TF for Fine Arts 15d: "Introduction to Italian Renaissance Painting and Sculpture," says she sees herself as more of a primary instructor because of the opportunity for close contact with students.

Katalin Makkai, who has been a TF in philosophy and has also taught in the Moral Reasoning section of the Core, says she considers TF autonomy to be an important factor to learning.

Makkai cites the trust of professors for TFs as a strength in the structure of courses she has taught.

"I always felt I was given lots of leeway to use my own judgment about how students are doing and what they need," Makkai says.

Because of their proximity to the students, TFs can offer important insights and approaches to course material, says Associate Professor of Economics Andrew Metrick.

"You work as hard as you can to get yourself in the shoes of the students but that gets harder and harder the more you've taught the material," he says.

"At Harvard, you guys are blessed because the graduate students are great," Metrick says.

Peers Teaching Peers

The use of undergraduates as TFs has further complicated the debate over their role in course instruction.

"About five years ago, with some trepidation, I started using a few very good undergrads as TFs," Davis says, noting that he only appoints students he knows to be strong and who are eager to teach.

Wallace Professor of Applied Physics R. Victor Jones, who has used undergraduate TFs for a number of years, says that his experience has been "very positive."

"In the areas where I'm most concerned, undergraduates have a tremendous amount to offer, and we would be hard put to do as good a job without them," he says.