Much discussion about higher education assumes that the children of wealthy parents have all the advantages, and they certainly have many. But a new study reveals an area where they may be at a disadvantage. The study found that the more money (in total and as a share of total college costs) that parents provide for higher education, the lower the grades their children earn.

The findings -- particularly grouped with other work by the researcher who made them -- suggest that the students least likely to excel are those who receive essentially blank checks for college expenses.

The study -- "More Is More or More Is Less?" -- is by Laura Hamilton, an assistant professor in the School of Social Sciences, Humanities and Arts at the University of California at Merced, and was just published by the American Sociological Review (abstract available here), the flagship journal of the American Sociological Association.

Hamilton used data from three longitudinal federal databases -- the Baccalaureate and Beyond Study, the Beginning Postsecondary Students Study, and the National Postsecondary Student Aid Study. And she compared parental contributions and grades. Significantly, she also controlled for factors such as parental socioeconomic status. She argues in the paper that high wealth levels are associated with higher parental financial contributions, but also with other factors that contribute to academic performance (such as better high school educations, high aspirations for higher education, and so forth). Without controlling for socioeconomic status, those other factors may mask differences in patterns based solely on parental financial contributions.

And here she found -- across all types of four-year institutions -- the greater parental contributions were, the lower the student grades were.

This finding backs the idea that parental financial support can act as a "moral hazard" in that students make decisions about how seriously to take their studies without having personally made the investment of cash in their educations.

The impact of parental contributions on grades was lower (but still present) at highly competitive institutions. Generally the grades were lowest for students with high levels of support from their parents at private, out-of-state and more expensive colleges.

Before parents reading this article cancel those spring semester tuition checks and Facebook message their college-age kids to get jobs, there are two important caveats to the study.

One is that the study found a positive association (even controlling for other factors) between increased parental contributions and graduation over five years. In an interview, Hamilton said that she explained this finding (even if apparently contradictory with the results on grades) because those with minimal levels of parental support have a much more difficult job paying for college, and those who can't pay, can't graduate. "Kids who don't have funds, they don't stay," she said.

The second caution Hamilton offered about parental spending on higher education comes out of the qualitative research project that prompted the quantitative work just published. Hamilton explored the impact of parental financial support on a women's floor of a dormitory of a Midwestern public university, tracking student grades and interviewing parents. She found the pattern confirmed by her national data: many parents provided high levels of support only to be shocked (and, she said, angry) that their daughters weren't earning good grades.

A second pattern Hamilton discovered in that study of one dormitory (and that she believes is the case nationally) is that the lowest grades were earned by children whose parents essentially supported them without much discussion of student responsibilities. The negative impact of high levels of parental financial support was mitigated or eliminated by parents who set clear expectations for their children about grades, graduating on time or other issues, she said. This extends to all levels of parental support for students.

The problem is that most parents who give a lot of money are apparently less than demanding about expectations. Then, Hamilton said, the students find college to be a great experience, and not one they are going to endanger by failing. "They say 'I want to stay there, but I'm not going to work too hard while I'm here.' They stay in college but dial down their academic effort."

Hamilton stressed that she wasn't arguing that parents who can afford to pay for college stop doing so. Rather, she said, they need to focus on what they are paying for, and to link their financial support to goals. What parents need to do, Hamilton said, is "to make smart investments." That means evaluating the expense, and not just assuming that all spending during the college years has equal value. In other words, she said, a parent of means is wise to offer support so a child can take a meaningful but unpaid internship, but the parent isn't going to see any payoff from providing cash for spring break vacations.

'Paying for the Party'

Hamilton may be prompting a lot of uncomfortable discussions between parents and college-age children this year. In April, Harvard University Press will be publishing a book, Paying for the Party: How College Maintains Inequality that she wrote with Elizabeth A. Armstrong, associate professor of sociology at the University of Michigan. That book argues that affluent students -- very much encouraged by their colleges and universities -- waste time and opportunities in college on "a party pathway" organized by the Greek system. The work argues that students who bypass the system may suffer social costs, but are likely to emerge with a much better education.

Further Armstrong argues that the party system present at institutions with the affluent students to afford it ends up hurting the educational experience of all students.

Hamilton said that while it is easy to just blame students for these trends, colleges and universities "play an important role" that needs more examination.

When she has presented about her research to faculty members, many have seemed uncomfortable about the implications for their own children. Hamilton has two young children (too young, she said, for them to be worried about her research). She said that she does "plan fund a considerable portion of my kids' college experience," but she added, "not without a conversation about the job of the student."