Yale faculty members earn less on average than their counterparts at Harvard and Princeton at every professorial rank.

Salaries of full professors at Yale ranked sixth among all private institutions, at an average of $151,200 last year, putting Yale professors behind those at Rockefeller University, Harvard, Princeton, Stanford and the University of Chicago respectively, according to data collected by the American Association of University Professors.

Harvard’s full professors earned 11.6 percent more than Yale’s, while Princeton’s made 3.7 percent more. Yale’s average associate professor salary ranked seventh at $85,300, and the average salary of assistant professors was eighth at $72,800. These averages include faculty in all professional schools and academic departments except medical schools.

But University administrators said the numbers alone do not tell the whole story.

President Richard Levin said average salaries are difficult to compare because of variations between universities’ departments and schools. He said there is a range of compensation levels between academic departments, and department sizes account for the much of the disparity between the average salaries of Yale and its peers. For example, Levin said, Harvard has much larger business and law schools than Yale, and Princeton’s salaries are “biased upwards” due to the large size of its engineering program.

“It’s a market phenomenon,” Levin said. “Largely speaking, those people have alternative employment opportunities.”

Yale College Dean Peter Salovey said salary parity can be more accurately determined by comparing the pay of faculty in the same academic department at different institutions.

“If you instead compared an English professor [at Yale] to an English professor [at another university], my guess would be that the difference would be much smaller,” he said.

Salovey also said the numbers do not represent the range of salaries within a professorial rank, which differs greatly among schools. Furthermore, he said, Yale pays a certain amount into faculty retirement funds, and that the value of this contribution also varies from one institution to the next. Such benefits — which help attract faculty to the University — are not accounted for in average salary data, Salovey said.

“Our goal is to recruit and retain the very best faculty we can and that means we are always going to be competitive,” he said.

In addition, Salovey said, new professors’ salaries often reflect the cost of living in the city in which the university is located. New Haven has a lower cost of living than both Boston, Mass., and Princeton, N.J., according to data from Sterling’s Best Places Cost of Living Index.

The U.S. News & World Report’s 2007 national college ranking — in which Yale placed third — also acknowledged the University’s relatively lower faculty salaries. Robert Morse, director of data research for the publication, told the News in September that Yale’s ranking was largely due to its sixth-place score in the faculty resources category. Average faculty salary was the main criterion for the faculty resources score, which also took into account class size, student-faculty ratio, faculty degrees and the proportion of professors who work full time.

Deputy Provost Charles Long said faculty salaries are reviewed every year in an elaborate process that lasts for much of the spring semester. Faculty members submit activity reports at the end of the fall semester which are then assessed by department chairs and relevant deans, Long said. The reports are examined by the provosts who send them to committees to finalize salaries by around April.

Long said the administration pays close attention to departmental differences and faculty diversity when determining salaries.

”It’s a combination of productivity and experience,” he said. “We don’t pay attention to ages, just the number of years in the profession after earning a Ph.D., [and] we make sure that by accident we’re not favoring one gender.”

Physics Department chair Ramamurti Shankar said the main complaint he hears from faculty is that those who are internally promoted are rarely paid as much as outsiders who have been recruited and tenured. He said the University has acknowledged this issue but has yet to take major steps to correct the problem.

Shankar said a number of other universities have a “star” system that allows them to offer top professors much higher salaries than the median. Although Yale does not use such a system and thus cannot always offer prospective faculty a salary as high as they could earn elsewhere, Shankar said, the University is still very competitive and provides a number of other benefits.

“In the six years I have been chairman … we have never lost anyone because of salary,” he said. “They don’t come to Yale because of the salary.”

The University has an effective system of addressing salary issues and rewarding achievement, Shankar said. He said if a department chair wants to increase an instructor’s pay — if he is offered a position at another institution or wins an award, for example — the chair can recommend the change to administrators. The money for such a raise will not come out of the individual department’s budget and will thus not affect other faculty members’ salaries, Shankar said.

“They have never turned down what I’ve asked for in any serious way,” Shankar said.

Provost Andrew Hamilton said the key factors that determine faculty salary are contributions to scholarship, excellence of teaching and service to the mission of the University.