JACKSON, Miss. (AP) — Mississippi's Board of Education voted Thursday for more study on how scrapping a required U.S. history test would affect school ratings.

The board directed an internal task force to study whether it's possible to stop the test without changing scores used to assign A to F grades to schools and districts. Changing scores is unpopular because the board might assign grades in a way that reduces A-rated schools and increases F-rated schools.

A state commission beneath the board previously voted to stop giving the history test, and public comment on the proposal generally favored the change. Students formerly had to pass exams in history, English, algebra and biology to graduate. Now, there are alternate routes to graduate, but some Mississippi students still don't earn a diploma because they fail one or more of the tests.

Teacher groups and others who say students are overtested are seeking the change.

The state can't drop any of the three other high school tests because they're federally required, but can stop giving the history test. However, the history test is counted in the state's grading system, and the federal government would have to approve any change to the grading system. No changes will take place this school year, but Mississippi would have to act early next year in time to win federal approval to drop the test in the 2020-2021 school year.

The U.S. history class would still be a requirement for high school graduation.