The U.S. Department of Education is allowing California to bypass federal requirements by giving standardized tests in math and reading to millions of public school students this spring without publicly reporting results or using them to hold schools or teachers accountable.

The reprieve, good for only the testing season that begins in the state on March 18, ends a months-long standoff between California and the department over the state’s testing plans.

At one point, Education Secretary Arne Duncan had threatened to withhold at least $3.5 billion in annual federal funding — money that California uses to educate poor and disabled children.

But in a letter sent to California officials Friday, Assistant Education Secretary Deborah Delisle wrote that her department has approved the state’s plan. “I hope you find this flexibility helpful,” she wrote.

She has issued similar approvals in recent months to Montana, Idaho and South Dakota.

Like most of the country, California rolled out new K-12 standards in math and reading this school year, requiring new curricula, materials and teaching approaches. But tests based on those new Common Core standards will not be ready until 2015. That’s a problem because federal law requires states to test students in math and reading every year in grades three though eight and once in high school.

California and other states faced a quandary: Should they just dust off their old tests, which don’t relate to the Common Core, and hope for the best?

California lawmakers voted overwhelmingly to scrap the old tests and give field tests, with sample questions, of the Common Core exam that is still being put together.

Because a field test is not designed to be a reliable measure of student achievement, California will not score the tests, and the results will not be publicly reported. The state intends to use test scores from last year’s standardized tests to make decisions about school performance, essentially maintaining the status quo for this transition year, officials said.

Tom Torlakson, California’s superintendent of public instruction, and Michael Kirst, president of the State Board of Education, said in a joint statement that they appreciated the Obama administration’s approval of their plan, calling it a “welcome vote of confidence. . . . Approval of this waiver could not have come at a better time. In little more than a week, some three million students will begin the largest field test of these new assessments of any state in the nation.”

California’s testing plan — and the Education Department’s approval — has angered critics, who say the strategy will deprive educators of valuable data and means students will be asked to take a test without meaning.

“It is frankly astonishing that as California makes the critical transition to new, higher standards for students, the state would assess more than three million children and then throw away the results,” Rep. George Miller (D-Calif.), ranking member of the House Committee on Education and the Workforce, said in a statement. “We don’t test kids just to test them. We test them to see how well they are learning and how teachers can improve their craft.”

Data from field tests should not be used to evaluate teachers, decide whether students proceed to the next grade and make other high-stakes decisions, Miller said. “But it can and should be available to help districts and schools adjust their strategies to meet student needs,” he said.

California will administer the Common Core field tests to all 3.4 million students in the designated testing grades, at a cost of about $51 million.

Arun Ramanathan, executive director of Education Trust-West, a nonprofit group that works to close the achievement gap between poor and affluent students, said officials in several school districts are frustrated because they want to see the results of the field tests.

“Don’t we want to know how it went?” he said. “We’re not getting any information back. These tests are publicly funded. We should know what happened, how students did on the very basic issues — whether or not they completed it, how many questions they answered correctly, etc. That information is useful for educators and system leaders.”

Dorie Nolt, a spokeswoman for the Education Department, said a one-year lapse in data will not harm students. “In any state, including California, that receives this flexibility, there will be no lessening of supports for struggling students,” she said in an e-mail.

The argument over what kind of test to administer coincides with a raging national dispute over the Common Core standards themselves.

Supporters say the standards emphasize critical thinking and analytical skills, as opposed to rote learning, and will enable U.S. students to better compete in the global marketplace.

Opponents include tea party activists who say the new standards amount to a federal takeover of local education and progressives who bristle at the emphasis on testing. Some academics say the math and reading standards are too weak; others say they are too demanding, particularly for young students.