Federal student aid -- with its various needs tests -- generally goes to low income students. But federal tax breaks for college costs, largely adopted during the Clinton administration, are having a significant impact on the amount of federal assistance going to wealthier students.

The average tax benefit received by families with incomes of $92,000 or more was greater in fact than the average benefit for those with incomes less than $32,000. This analysis comes from "Student Financing of Undergraduate Education: 2003-4," released Wednesday by the National Center for Education Statistics. While the report is an annual look at tuition and financial aid, the study released Wednesday had the most thorough analysis to date of the impact of federal tax breaks as a student aid tool.

When the tax breaks were created, and in the years since, some critics have predicted that they would end up helping students who least need the help, and the new data are likely to reinforce that impression. Defenders of the tax credits have countered that many middle class families need support and that Congress and the administration are unwilling to make large increases in Pell Grants or other programs that are more focused on low-income students.

Data in the new report show that tax breaks make up a relatively small share of student aid for low income students, but the majority of aid for wealthier students.

Average Federal Aid for Full-Time Undergraduates, 2003-4

The report notes that the impact of tax breaks on wealthier families isn't shocking. To get certain tax breaks, you need to have sufficiently large tax bills and the size of tax breaks is linked to tuition costs. To the extent wealthier families (1) have the higher tax bills to start with and (2) are more likely to attend more expensive institutions, the impact makes sense.

More generally, the data released in the report show the widely varying economics of higher education -- including both costs and sources of support -- by sector. Tuition, for example, is a relatively small share of total costs for students attending community colleges, but represents the most significant expense by far at private, nonprofit institutions. And relatively small proportions of students borrow at community colleges, but large proportions borrow in other sectors.

Financial Characteristics of Full-Time Undergraduates, 2003-4

The report also includes a wealth of other data that, while a few years old, tends to be more detailed than more recent data. There are numerous tables on enrollment patterns, average tuition costs and demographics.