The gap between the highest- and lowest-paid faculty members at American colleges and universities continued to expand in the 2006-07 academic year, according to a study released Thursday.

The study, released by the American Association of University Professors, said athletic coaches and university presidents are nationally among the highest-paid faculty members, while humanities and social science professors are the paid the least.

John Curtis, director of research and public policy at the AAUP, said the growing gap in salaries between faculty members working in different disciplines is largely controlled by the private sector.

"Humanities and social sciences have the lowest salaries and fewest jobs outside of academia," Curtis said. "These professors can be paid less because they have [fewer] options in the private sector."

University of Wisconsin Provost Patrick Farrell said at UW, finance and business professors are among the highest paid because of their increasing demand outside the academic world.

"People with the skill sets of our faculty are in high demand in the business and high tech worlds and [at] pharmaceutical companies," Farrell said.

Competition with other institutions, Ferrell added, is another factor driving up faculty salaries.

And Curtis said there is also an upward spiral of salaries for college administrators — a trend he expects to continue in the future.

"There is a move to pay college and university presidents as if they were more like corporate CEOs," Curtis said.

A university president makes, on average, three times more money than a full-time faculty member at the same institution, according to the AAUP study. And to put the earnings into perspective, college and university presidents' salaries, Curtis said, are often compared to the salaries of presidents at businesses and corporations.

Curtis added it is important to compare presidential salaries to faculty salaries at the same institution to understand the growing gap in wages.

At UW, the gap in wages continues, as Farrell said faculty received an average raise of 4.3 percent in the 2006-07 year. Professors' raises, Farrell added, are initially decided at the department level and then reviewed by the deans on a performance basis.

"Merit raises are based on who outstanding performers are," Farrell said. "Tenure is not as big of a thing as performance."

However, chancellors' and provosts' wages, Farrell said, are determined by the Board of Regents.

The study also said football coaches' compensation averaged approximately $1 million nationally, though division I-A coaches make substantially more, with room for bonuses if their team has a successful season.

But Curtis said most schools in the United States do not make money from their athletic programs.

"Only a minority of schools make a net profit with athletic programs," Curtis said. "[It] becomes a question of the extent the educational missions of the university being changed by the emphasis on spending money on athletics."

Curtis said the growing salary gaps show the core mission of a university — to provide a quality education — may be changed by excessive spending on athletics.

Yet Farrell maintained football is not as important as academics at UW. He added the market drives up the cost of retaining a successful football coach on staff, a high price many schools are willing to pay to maintain their reputations.

"If you pay more, you get a better coach," Ferrell said. "We hold excellence in the highest regard in everything we do, including athletics."