Texas’ top higher-education official has joined parents and students in the state in worrying about the ramifications of a law changing how high-school grade-point averages will be calculated, according to today’s Austin American-Statesman.

The law, passed last year by the state’s Legislature, requires the Texas Higher Education Coordinating Board to come up with a new, standardized method of calculating high-school students’ grade-point averages, with additional weight to be given to more-rigorous courses. The measure requires the board to develop the new formula in time for it to be applied to students seeking admission to college in the fall of 2009.

In a letter sent last month to the state’s attorney general, the commissioner of higher education, Raymund A. Paredes, said the law had left unresolved several key questions, such as whether school districts will be required to use whatever formula the board devises. He also said he was concerned about the prospect of legal challenges from students whose GPA’s drop as a result of the recalculation — and from their parents.

Under the law, students entering 12th grade this fall will see their GPA’s recalculated for college applications in ways that could reward or punish them for their course selections as freshmen, sophomores, or juniors. Some of those who are now ranked in the top 10 percent of their high-school class could drop out of that tier, causing them to no longer be guaranteed admission to any public university in the state.

In his letter, Mr. Paredes said he was worried that changing the weight assigned to students’ past grades would leave the state open to legal challenges based on a provision in the Texas Constitution stating that laws cannot be retroactive. —Peter Schmidt