Current levels of need-based student aid may not be sufficient to help all qualified high-school students from low-income backgrounds attend college, according to a report scheduled to be issued today.

The report, "Investing in America's Future: Why Student Aid Pays Off for Society and Individuals," was a joint project of the Institute for Higher Education Policy, a nonpartisan research group, and Scholarship America, an organization that distributes student aid.

The authors of the report examined trends in student-aid financing and did a cost-benefit analysis of the aid. Based on that analysis, the report links increased student aid to a host of societal benefits, including higher tax revenue, lower unemployment, greater productivity, reduced reliance on public assistance, decreased crime, and increased quality of health.

Those findings come just days before the U.S. House of Representatives is expected to take up legislation to renew the Higher Education Act, which will shape federal policy on student aid for the next five years.

Need-based aid, according to Jamie P. Merisotis, president of the Institute for Higher Education Policy, has not yet emerged as key issue in the debate over how to renew, or reauthorize, the act.

"There's not much discussion about investment in need-based financial aid in reauthorization so far," Mr. Merisotis said. "It's not surprising in some ways, given the current federal budget situation, but as we point out in the report, it's an investment and it does have a payoff. I hope short-term budget problems don't end up influencing long-term needs we have in terms of getting more low-income people into and through college."

The report says that societal benefits can best be achieved through need-based grants, which have declined as a portion of total aid in recent years as governments have put more dollars into merit-based awards. For instance, the report cites statistics showing that in the past three decades, need-based grants have gone from 61 percent of all federal student aid to 22 percent.

"There's nothing wrong with trying to promote academic merit," Mr. Merisotis said. But if merit grants are replacing need-based ones, "we are doing a disservice to low-income populations," he said. "That support is important because we all benefit as a society from that investment. It's not about them -- it's about our collective interest as a nation."

The report shows that the gap in college-going rates between affluent and needy students has hardly budged in 20 years. If current levels of financing for need-based aid continue, that gap is likely to widen, the report says.

To remedy that trend, the report recommends that the federal government double the maximum Pell Grant award, to about $8,000 instead of the current $4,050. It also suggests that policy makers refocus student aid toward need-based grants and work more closely with the private sector to secure revenue for scholarships.