For students in departmental humanities classes, the phrase "teaching fellow" often conjures up a polished third-year graduate student who facilitates student discussions and divines student grades with the aid of years of related study under his belt.

For students in science classes, however, the image evoked is rather different. Not only is section more often than not an autocratic session of deciphering and demystifying course materials, but section leaders are frequently mere undergraduates who took the course the previous fall.

In some departments, like chemistry, teaching staffs for courses include just a smattering of seasoned and scholarly upperclassmen.

In other fields, particularly computer science, a first-year student's prime purveyor of academic wisdom and indelible transcript markings is more often than not some clever sophomore freshly consigned to the Quad.

Undergraduates teaching their peers raises a number of questions and possible ethical dilemmas, not the least of which is "Should I be paying $35,000 a year to be taught by my blockmate?"

Despite the possible problems with undergraduate Teaching Fellows (TF), a shortage of graduate students makes them necessary in some departments. Many say, however, that undergraduate TFs are not only a necessity, but are welcome additions to teaching staffs.

Not Enough To Go Around

The use of undergraduate TFs to teach introductory math and science courses arose initially out of the shortage of graduate students to fill all the necessary positions.

"We normally place the grad students in the higher-level courses, such as organic and Chem 10," says Senior Lecturer James E. Davis, who teaches Chemistry 5: "Introduction to Principles of Chemistry," "but we usually run out of grad students before filling all the slots in Chem 5."

Davis says graduate students in the Chemistry Department are typically given priority for teaching jobs, but there simply aren't enough of them to fill every post available.

This scarcity of teaching fellows is especially noticeable in departments that are growing rapidly. In computer science, where the number of concentrators has recently ballooned to 250, the teaching staffs of most introductory courses are composed entirely of undergraduates.

"The situation arose out of necessity," says Associate Professor of Computer Science Steven J. Gortler, the department's director of undergraduate studies.

With roughly 30 or 40 graduate computer science students, "all the positions simply can't be filled with the graduate student population here," he says.

"Had there been lots of graduate students I think a more traditional setup might have occurred," he adds.

Understanding Teachers

Necessity or not, some professors and students claim that undergraduate TFs are actually preferable to graduate students.

Senior Lecturer Henry H. Leitner, who teaches Computer Science 51, the notoriously grueling departmental introduction to object-oriented programming, says he believes undergrads are better suited to teaching his course because the students he hires have taken the course very recently and so are intimately familiar with the concepts and assignments.

"Undergrads are much more in tune with what students know and don't know," Leitner says.

Besides having fresh memories of the material, undergraduate TFs can be advantageous in other ways as well, according to Andrew P. Marcus `01, a chemistry concentrator and currently the lone undergraduate teaching fellow for Chemistry 7: "Principles of Chemistry."

"A lot of first-year grad students don't speak English well, which can be a problem in section," he says.

In addition, because undergraduates are not forced to teach to maintain departmental support, as most graduate students are, those that choose to do so are often more enthusiastic about teaching than their graduate counterparts.

"All the undergrads who TF really want to do it, and throw themselves into it with great enthusiasm," says Davis, the Chemistry Department head tutor. "Many of the grad students are outstanding TFs, but not all the grad students really want to teach."

"They have generally done excellent jobs, and in fact have won more Bok Center teaching awards than the grad student TFs," he says.

Learning Through Teaching

Gortler, who teaches computer graphics, says when he first came to the College he didn't think TFing was the best way for undergraduates to be spending their time.

Having seen undergraduate TFs benefit from the experience, however, he has since changed his mind.

"I think the students who do TFing get quite a bit out of it," he said.

These benefits include getting to know course material extremely well, developing strong relationships with faculty and other students, and improving key presentation and explanation skills.

To help students develop these skills, all students who teach at the College must undergo a two-day training program at the Bok Center for Teaching and Learning. The center video tapes students and provides constructive feedback.

"They remind you of the little things," says Vicky Zhao, a sophomore currently TFing CS51, "like stand to the left side of what you're writing."

Bright Young Things

Zhao, also a Crimson editor, says she really enjoys helping students struggle through the course's difficult material, though she admits teaching it has been a challenge.

"When TFing, especially at a place like Harvard, you always get one or two kids in your section who are very bright and try to outdo you."

This can be especially problematic when students are teaching peers who are only slightly younger, and quite possibly even older, than they themselves are.

Amos B. Blackman `01, a CS concentrator who has been TFing departmental courses since his sophomore year, says that he has occasionally received these complaints.

"I have had a few students complain to me personally that they 'couldn't believe they're being taught by someone younger than them, it's offensive and ridiculous,' and I always calmly reply, 'What's wrong with their teaching?' They can never answer that question," he says.

While in the humanities, such a scenario would likely be disastrous, Gortler says he thinks it is a formula which works in the sciences.

"Perhaps because there's less of an element of subjectivity, there perhaps isn't as much of a need to have a difference in ages for students to respect their teaching fellows."

Living in the Terminal Room

Even trickier than the task of teaching overachieving peers about computational complexity or multivariable calculus is the challenge TFs face of balancing teaching responsibilities with other academic and extracurricular obligations.

While most TFing positions require only between 10 and 20 hours of commitment a week, some students find themselves giving considerably more.

David D. Eggli `03, a CS51 teaching fellow, says officially TFing the course is only supposed to require about 50 hours per month.

"Truth be told, it's generally closer to 50 a week," he says.

In addition to time spent grading problem sets, which he says take about an hour each, every week he is responsible for preparing for and teaching an hour-long section, attending a weekly TFing meeting, attending three hours of lecture, responding to a deluge of student e-mails, and holding two office hours in the basement of the Science Center helping students debug their programs.

In reality, though, he says he often spends 15 or 20 hours on this last task, simply because so many students are in need of help.

According to Blackman, putting in the extra hours is actually quite enjoyable.

"I've always found it fun to hang out in the terminal room at 3 in the morning with the...students finishing, or starting, their assignments," he said.

Not Easy to be Hard

While most students in the sciences accept undergraduate TFs as a fact of life, their presence does raise some interesting ethical issues. Perhaps the stickiest of these is that of fairness.

To maintain fairness in his course, Leitner says that assignments are graded according to very detailed and precise grading standards, and sections are assigned so that no TF knows any students in his section.

In smaller, upper-level computer science courses, however, this is often simply not possible.

Blackman, a teaching fellow for CS161: "Operating Systems," says that because he already knew almost everyone taking the class, there was no way he could avoid teaching and grading his friends.

"The nice thing about CS is that you can be reasonably certain that you're grading objectively and fairly," he said. "No one's ever appealed to me as a friend for a personal favor when I've been a TF."

But Piotr Dollar `02, a Mind, Brain, Behavior concentrator, says that when it comes to handing in assignments late or getting extra help on problem sets, undergraduate TFs can be more accommodating than graduate TFs.

"It's easier to get away with things sometimes because you're already friends with them," he says.

Kevin C. Gold `01, a teaching fellow for CS50 last semester, says he thought grading was the most difficult aspect of TFing his fellow undergrads because it occasionally required him to decide whether or not to pass students who are really struggling.

"It's tough to be mean once in a while and not accept late assignments, or stick with an original grade, because a lot of it is entirely up to the TFs," he says. "We like being liked, but we also have to be just."

Despite the trials of grading, though, Gold says the experience has been very rewarding. He says TFing this year has not only given him the opportunity to try out teaching, but it has helped him decide whether or not he wants to go into academia.

"As a job, of course, it's wonderful. It feels as if I'm getting paid for doing a strange combination of academics and community service," he says.

"I'd definitely recommend doing it to anyone," he adds.

-Staff writer Camberley M. Crick can be reached at crick@fas.harvard.edu.