Under the Obama administration’s education policies, thousands of elementary and secondary schools are being held accountable for the academic performance of students who had been “invisible” under No Child Left Behind, the Bush-era federal education law, Education Secretary Arne Duncan said Thursday, the Washington Post reports. Duncan’s remarks came during a Senate committee hearing about No Child Left Behind [1]waivers [2] the administration has issued to 34 states and the District of Columbia since 2012. In addition to unleashing “great innovation and creativity” on the part of the participating states, the waivers have pulled in “hundreds of thousands” of students whose standardized test scores hadn’t been counted toward accountability plans for schools, Duncan said…