National Council on teacher quality:

State governments are arguably the most powerful authority over the teaching profession. Since 2007, NCTQ has tracked and analyzed teacher policies across all 50 states and the District of Columbia in our State Teacher Policy Yearbook. The Yearbook presents the most detailed analysis available of each state’s performance against, and progress toward, a set of specific, research-based teacher policy goals aimed at helping states build a comprehensive policy framework in support of teacher effectiveness.