ATLANTA -- The idea that college students who work on the side are at a disadvantage is almost quaint. Not because there's no evidence that spending many hours on things other than academics can impair students -- such evidence does exist -- but rather because the days are long past when many college students had a choice but to work. As tuitions have risen and more and more undergraduates are enrolling later in life, nearly half of all full-time students and 80 percent of part-time students work -- numbers that are likely only to grow in the future.

Given that reality, the more college officials and higher education researchers know about how working affects students' academic performance the better. And among the many sessions at last week's meeting here of the Association for Institutional Research about what seemed to be an unofficial theme -- what works and doesn't in retaining students -- were two that sought to provide a more nuanced look at the impact of different amounts and kinds of work on first-year college students' grades and other educational experiences.

The studies, whose authors include some of the most recognized names in research on students, offer somewhat conflicting findings, but combine to leave the overarching impression that it's a vast oversimplification to assume that work is necessarily bad for students' academic performance and engagement.

"When you're talking about throwing a factor into the very complicated soup that is higher education, it's a little oversimplified to say that one thing should affect college students across the board," said Mark H. Salisbury, a research assistant and doctoral student at the University of Iowa who presented one of the two studies at the institutional researchers' meeting. "It makes more sense that work could have positive effects on one thing and negative on another, and that it would affect different kinds of students differently. And that's what we find."

One of the two studies, which is based on data from the National Survey of Student Engagement, looked at how various amounts of on- and off-campus work directly influenced students' self-reported grades and indirectly affected their levels of engagement in academic activities.

Consistent with the conventional wisdom, said Gary R. Pike, lead author of the study, working more than 20 hours a week has a negative impact on students' grades, whether the the employment is on campus or off. Students who work 20 hours or less, on campus and off, report roughly similar grades as do students who do not work at all.

But the indirect relationships between employment and grades, as indicated by students' levels of engagement in "educationally purposeful activities," are more complicated, said Pike, executive director of information management and institutional research and associate professor of higher education and student affairs at Indiana University-Purdue University at Indianapolis.

Students who work 20 hours or less a week on campus report higher levels on all five levels of engagement used by Pike and his co-authors, Indiana University's George D. Kuh and Western Kentucky University's Ryan Massa-McKinley, measurements that included such things as student-faculty interaction and engaging in active and collaborative learning. Working 20 hours or less off campus strengthens students' performance on two of the five engagement levels, while students who work 20 hours or more, on campus or off, "did tend to be more engaged than students who did not work at all," said Pike. That is likely to be because such students have developed strong time management skills, Pike said.

When combining the direct and indirect impact on grades, though, working more than 20 hours a week on campus or off negatively affects students' academic performance, as the significant time that students spend working ultimately drags down their grades. But for students who worked less than 20 hours a week, where they worked was an important differentiator, Pike said, with those who worked on campus reporting a net positive gain in grades, while those who worked off campus felt a significant negative effect.

The implication of the results, the study's authors suggest, is that "creating meaningful work experiences for students on campus is a key element in an overall strategy designed to foster student achievement and success." That is a challenge on many campuses, though, as many colleges have relatively few such opportunities, Pike said. He speculated that many campuses may be feeling pressure, as the economy turns down, to transform part-time opportunities for students into full-time jobs to improve efficiency.

Looking Beyond Grades

The second study -- on which Salisbury worked with Ernest T. Pascarella and Ryan D. Padgett, colleagues at the University of Iowa's Center for Research on Undergraduate Education -- sought to examine the impact of work on things other than pure academic performance, in the recognition that colleges are increasingly being judged by a broader series of outcomes for their students. Using data collected as part of the Wabash National Study of Liberal Arts Education, the researchers looked at how students who put varying hours into on- and off-campus worked fared on measures such as critical thinking, moral reasoning, socially responsible leadership, and psychological well being.

While this study, like Pike's, found some negative effects of working off-campus more than 20 hours a week -- for instance, bringing down students' performance on critical thinking -- it also found that doing so had a positive effect on student's psychological well being, and that students who worked off campus also trended positively on leadership skills.

"Work doesn't really have much of a negative effect on cognitive-type outcomes like moral reasoning and critical thinking until you get to a ton of hours," said Salisbury. "But work has a positive effect on things like psychological well being and leadership even when you're working a ton of hours."

But there were significant differences in the impact on students who came into college with varying academic abilities, with much more harm done to students who scored lower on college entrance exams. Working on campus between 1-10 hours a week had a positive effect on critical thinking for high-ability students but a strong negative effect for low-ability students, the study found.

That finding suggests that college financial aid officials should take pre-college academic ability into account when shaping the mix of grants, loans and work study in students' financial aid packages, Salisbury said. "For a high-ability kid, none of the things in that mix is likely to be detrimental," he said. "But for a low-ability kid, especially those from lower socioeconomic backgrounds, when they get big loans, they tend to dial back the loans and crank up the work hours because the only way to pay the loans back is through their own work."

The study's findings suggest that the recently enacted increase in federal work study funds is positive, but that new campus jobs should be structured to require as much intellectual engagement and accountability as possible, since those are the aspects of off-campus jobs that tend to build leadership and psychological well being, Salisbury said.

He also suggests that the government consider significantly expanding the Job Location and Development Program, an element of the federal work study program that focuses on off-campus jobs. (Note: This paragraph was updated to correct an error.)