A study released last week revealed that last fall, only 40 percent of College of Arts and Sciences courses were taught by professors who were tenured or on tenure track.

But administrators say the numbers may not be as telling as they seem.

Of the 1,228 classes offered -- not including recitations -- 490 were taught by full professors. Lecturers, adjunct faculty and graduate students taught the bulk of the classes last semester.

The report, called "Casualized Penn: Where Did The Professors Go?," was released by Graduate Employees Together -- University of Pennsylvania, a graduate student group seeking recognition as a union by the Penn administration.

The study was conducted by third-year Ph.D. student Ciara Kehoe. She used Penn's online Course Register to tabulate all the College courses offered last fall. She then used the Penn Directory to identify the job classification of each instructor: professor, lecturer or graduate student.

A similar report was released by the Graduate Employees and Students Organization, a counterpart to GET-UP, at Yale University a few years ago.

However, College Dean Rebecca Bushnell said that the data presented in the report were skewed. She said that, because of the nature of the SAS curriculum, there are numerous language classes and writing seminars that are taught by trained language instructors or professional teachers and are also capped at 15 to 20 students per class.

"Tenured and tenure-track professors are still teaching the core undergrad program outside of the language and writing classes," Bushnell said. "Our peer institutions do exactly the same thing."

But GET-UP representatives say Penn undergraduates are not getting their money's worth.

Because the Penn administration relies on temporary instructors -- who are paid less than tenure-track professors -- students are not being taught by faculty members who are working at the cutting edge of their fields, GET-UP spokesman Bill Herman said.

Herman added that many of the junior lecturers and graduate students are often underpaid and do not have job security for the next semester.

As a temporary instructor, "one has so many other things to worry about. ... That becomes a huge distraction when teaching a class," he said.

Bushnell is confident that the SAS will acquire more and more tenure-track faculty. Her strategic plan -- a five-year proposal that she laid out when she was appointed dean in 2004 -- calls for a 10 percent increase in the number of tenure-track faculty in the next five years.

However, College junior Dylan Bordonaro -- who is taking a Cinema Studies class taught by a visiting faculty member -- said that having non-professors teach a class sometimes allows more student-teacher interaction and brings a new perspective into the class.

"While on one hand you don't have all the knowledge that professors have ... people who aren't so busy with their research are better communicators of knowledge, as opposed to a professor on tenure," Bordonaro said.