Undergraduates at Northwestern University learn more from nontenured professors in introductory courses than from professors with tenure, according to a study released Monday by the National Bureau of Economic Research.

The study looked at more than 15,000 first-semester freshmen at Northwestern University from 2001 to 2008, comparing their long-term performance in subjects taught by tenure-track professors with their performance in subjects taught by a lecturer or long-term adjunct.

According to the study, evidence from students’ performances in subsequent classes suggested that taking classes with nontenured instructors encouraged students to take more classes in the initial subject taught by them than those who took classes with tenured professors did. Students were also shown to do better in subsequent coursework.

“There is an increasing reliance on non-tenure track instructors across a wide range of universities,” said David Figlio, director of the Northwestern Institute for Policy Research and one of the authors of the study, in an email. “It is reasonable to expect that people who are hired, retained and promoted largely on the basis of teaching excellence would be more likely to be effective teachers than … (those) on the basis of research excellence.”

UC Berkeley is not a private university, but Martha Olney, a UC Berkeley adjunct professor in the economics department who teaches Economics 1, said the results do not surprise her and that she expects results to be similar were a study conducted at UC Berkeley.

“Being an adjunct here is self-decided, and you wouldn’t apply if you didn’t like teaching,” Olney said. “Your job retention as an adjunct is tied to your performance.”

According to Olney, less than one-third of tenure at Berkeley is based on service and teaching, and more than one-third is based on research. She said having more of a teaching emphasis track would be beneficial to any institution.

However, C. Judson King, director of the UC Berkeley Center for Studies in Higher Education believes the results of the study are unique to Northwestern University as a private institution.

Ethan Shagan, campus history department chair who previously taught at Northwestern University, sees UC Berkeley as a place for teaching students to achieve the highest level of thinking in all disciplines, which can only be learned from people engaged in cutting-edge research.

“(Studies like these) assume a sort of dumbed-down model of the university, where we are glorified high school teachers whose goal is to better teach students rote memorization … that they can parrot back on an exam,” Shagan said. “The goal is to teach students to think for themselves, and that’s not something adjuncts can necessarily do as well.”

Figlio agreed that top researchers also have special knowledge that “might spill over” into the classroom.

“Berkeley and Northwestern have many similar attributes,” Figlio said in an email. “Our study suggests that it may be reasonable for a top research university like Berkeley or Northwestern to hire…(faculty) somewhat more teaching-active.”