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Nationally, the number of part-time faculty at American colleges and universities has increased significantly in the past two decades. But Yale has not followed that trend, said John Goldin, director of Yale’s Office of Institutional Research.

The Chronicle of Higher Education reported Tuesday that the number of part-time faculty members increased by 79 percent between 1981 and 1999. The American Council of Education conducted the study using data from the U.S. Department of Education.

At Yale, many non-ladder faculty — who are not eligible for tenure — are full-time professors and fulfill specific teaching needs, Yale College Dean Richard Brodhead said.

“We have been very mindful of the situation,” Brodhead said. “In places where there’s a lot of introductory teaching you want to hire someone with that expertise — it is our expectation that the first line of defense to get teaching done is the faculty.”

Brodhead said no regular faculty member is exempt from teaching at Yale, which is not necessarily the case at other universities. Roughly 90 percent of the instruction in the Faculty of Arts and Sciences is done by full-time faculty, Goldin said.

Goldin said the term “ladder faculty” at Yale is what other schools call tenure track. For assistant faculty, he said, there is a 10-year time limit to be tenured — the “up or out track” — but for non-ladder faculty different rules apply.

The Chronicle reported that the national increase in part-time faculty is a result of many factors, including an economic downturn and a national increase in college enrollment. More than 400,000 of the one million instructors at American colleges and universities are part-time.

Goldin said the issue of part-time faculty gets cast in different terms at Yale than at other schools across the country.

“We have had an increasing number of non-ladder faculty, but we also have had an increasing number of courses taught,” Goldin said. “In the past couple of years there’s been a reverse of both those trends.”

Yale’s non-ladder faculty include adjunct professors and some lecturers. In the fall of 2001, there were 810 non-ladder faculty members at Yale, according to the Office of Institutional Research.

Goldin said the School of Drama and the School of Music do not use tenure, so the regular core faculty at those schools are all adjunct professors even though most are full-time.

Brodhead said introductory professorships in the foreign language and English departments are instances in which “you would like to run a search for a specific teaching need.”

Goldin said some academic areas of the University heavily emphasize small class size. Those areas tend to use faculty members at a variety of levels, including part-time professors, to lead sections.

“There are some places where there is more use of part-time faculty, like intro English,” Goldin said.

Nina Garrett, the director of the Center for Language Study, said it is Yale’s philosophy to build up a number of highly-trained, professional language teachers.

“There have been moves in the past to consolidate part-time positions into full-time positions with full benefits,” Garrett said. “The general philosophy is to go for a committed full-time group rather than spread it out among part-time positions — In that regard we are going against the national trend and I am extremely proud of it.”