WASHINGTON (AP) — Most of the states that first endorsed the Common Core academic standards are still using them in some form, despite continued debate over whether they are improving student performance in reading and math.

Of the states that opted in after the standards were introduced in 2010 — 45 plus the District of Columbia — only eight have moved to repeal the standards, largely due to political pressure from those who saw Common Core as infringing on local control, according to Abt Associates, a research and consulting firm. In Oklahoma, Gov. Mary Fallin signed a bill to repeal the sta...