California Gov. Jerry Brown signed a bill Wednesday ending the traditional standardized tests that the state's public school students have taken in reading, math and social science since 1999.

Assembly Bill 484 replaces the pencil-and-paper, multiple-choice tests with new language and math tests that are taken on computers.

The new assessments are designed to follow a set of national curriculum standards known as Common Core.

Because the new test still is under development, schools will be required to give it in grades 3-8 and 11 in either math of language this spring, but not both, and no individual student scores, school performance reports or statewide results would be generated from the rollout.

U.S. Secretary of Education Arne Duncan has threatened to withhold federal funds from the state if it moves forward with the plan.

As state lawmakers debated AB 484 last month, Duncan warned them that abandoning traditional testing will limit the ability to determine school performance through year-to-year test score comparisons.

"...Letting an entire school year pass for millions of students without sharing information on their schools’ performance with them and their families is the wrong way to go," Duncan said in a written statement.

However, in a visit to San Diego in September, Duncan backed off the threat somewhat by saying the state and the federal government needed to work together.

California Superintendent of Public Instruction Tom Torlakson has likened the act of continuing the standardized tests as looking in the rear-view mirror.