WASHINGTON (AP) — Federal Reserve Chair Janet Yellen said Wednesday it would be a serious mistake for Congress to require the nation’s central bank to adopt a formal policy rule to guide its decisions on setting interest rates.

Yellen faced a barrage of questions from Republican lawmakers about legislation that they are supporting to make the Fed more accountable and make its policy decisions more transparent. One of the requirements would have the Fed adopt a policy rule that would govern future decisions and would have the Government Accountability Office audit the rule.