In a ruling that leaves more questions than it answers, the Internal Revenue Service says it will allow colleges and universities to determine how much of a contribution to an athletic scholarship program is tax deductible.

The ruling supersedes and expands on a 1984 ruling that would have made it more difficult to deduct contributions made to qualify for preferred seating at athletic events. Now, the schools will determine in advance the "fair market value" of such tickets, with only the excess amount of the contribution being considered a gift and, therefore, tax deductible.

The ruling affects only individual taxpayers. Corporations still will be able to write off the entire cost as a business expense.

The ruling is likely to have little effect on contributors who get season tickets at Maryland, Georgetown and Virginia. But it could affect the deductions of those who give large enough amounts to qualify to buy tickets for the Atlantic Coast Conference and Big East basketball tournaments, for which there is no public sale.

At Maryland, for instance, it takes a $1,500 annual contribution to qualify to buy two ACC tournament tickets costing $90 each.

The ruling is vague as to what constitutes fair market value. "In making the estimate, the university considered the level of demand for tickets, the general availability of seats, the relative desirability of seats based on their types, location and views, and other relevant factors," the IRS ruling said.

Steve Pyrek, an IRS spokesman in Washington, said the agency planned to issue no further guidelines for determining fair market value. "Somebody somehow would have to determine what a willing buyer would pay to a willing seller for that," Pyrek said.

The only input the IRS would have into the process would be during audits of taxplayers claiming the deduction.