Under the federal No Child Left Behind Act, poor children in persistently failing schools are entitled to receive free tutoring on the government's dime. But two years after the law was signed, only a small portion of the students eligible for those services are receiving them. The supplemental-services requirements have prompted more than 1,000 tutoring providers to secure spots on state lists of approved providers, according to researcher Siobhan Gorman, who analyzed the emerging market in a paper for the American Enterprise Institute, a Washington think tank. As the accountability requirements of the No Child Left Behind Act grow steeper, so does anticipation that more schools will be required to provide tutoring.