WASHINGTON — Efforts to save up for a first car or stretch an allowance might be helping high schoolers in at least one academic area.

Twelfth-graders did better on a recent national economics test than they did on similar math or reading tests, according to results released yesterday.

Forty-two percent of 12th-graders nationwide scored at the proficient level or better on the economics test, meaning they could handle challenging subject matter.

In contrast, just 23 percent of 12th-graders hit the proficient mark in math, according to results published earlier this year. In reading, 35 percent were proficient or better.

It is assumed a student needs a strong foundation in math and reading to do well in economics, so the relatively strong economics results are likely to raise questions.

One explanation may be that the federal reading and math tests are harder than the economics exam. This was the first time economics was offered as part of the National Assessment of Educational Progress.

Darvin Winick, chairman of the National Assessment Governing Board, which oversees the tests, said the economics exam included questions about personal finance as well as topics such as market economics and international trade.

Winick said high schoolers may be picking up lessons about personal finance outside of school — such as at home or at work.

Winick called the economics scores encouraging, noting that high school seniors are nearing independence. "It's comforting that they would know the difference between an asset and a liability," he said.

Economics courses are becoming increasingly common in high school. A 2005 survey of transcripts found 66 percent of high school graduates had taken an economics class, up from 49 percent in 1982.

Students who took a high-level economics course, such as one labeled Advanced Placement or honors, were more likely to score high on the national test than students who did not take a similar course, according to the governing board.

But high schoolers who took a general economics course did not do any better on the economics test than students who didn't take a class, which raises questions about the rigor of those basic-level courses. It's also possible that students are getting some information about economics through other courses.

Students scoring at the proficient level on the economics test should be able to analyze the effect of a poor harvest on the supply of an agricultural product and determine the impact of a drop in oil production on countries that import oil, among other things.

Seventy-nine percent of 12th-graders who took the economics test demonstrated an ability to at least do basic-level work.

That, too, is higher than the percentage of kids reading and doing math at least at the basic level.

Students working at the basic level should be able to describe a benefit and a risk of leaving a job to go to school and should be able to identify the relationship between a person's credit history and the interest rate attached to a loan.