Texas has formally sought a wavier from the U.S. Department of Education to avoid accountability standards imposed by the No Child Left Behind law.
   The state had been one of 11 nationwide not to seek a reprieve from some mandates of the federal policy. But Education Commissioner Michael Williams announced in September that Texas would change course.
   Williams' agency said Friday it had submitted a letter seeking to forego accountability standards and to avoid at-risk student intervention guidelines in favor of existing state policies.
   Previously, Texas had not sought a wavier because of fears the federal government might eventually impose a national curriculum.
   Last year, nearly half of Texas' public and charters schools failed to meet No Child Left Behind accountability standards, which are getting more rigorous annually.