As policymakers debate the merits of new tests and intervention strategies to improve student achievement, some districts are exploring a more basic warning sign: Are students even showing up? A growing consensus of research points to chronic absence--defined by the national policy group Attendance Counts as missing 10 percent of school or more--as one of the strongest and most often overlooked indicators of a student's risk of becoming disengaged, failing courses, and eventually dropping out of school. Most districts collect attendance data on their students, but few know what to look for when they review it, said Hedy N. Chang, the director of Attendance Counts, a national policy group. In Maryland, schools are required to report any student who misses more than 20 days of school. In 2009, district officials, researchers from Johns Hopkins University and the Baltimore Education Research Consortium, as well as more than 100 representatives from foundations and corrections and social service agencies, joined forces to create the districtwide Baltimore City Student Attendance Work Group, which studies the problem and suggests solutions. The district has moved to require an attendance monitor in every school, as well as districtwide incentives for students to come to school more often and education for parents and teachers on the importance of attendance. The district is also getting the students involved in spreading the word about the importance of school attendance.