Chronic absenteeism--or missing 10 percent or more of school days for any reason--is a proven early warning sign of academic risk and school dropout. Too often, though, this problem is overlooked, especially among elementary students, because of the way attendance data are tracked. This study confirms the premise that districts and schools may fail to detect high levels of chronic absence because the problem is easily masked by average daily attendance, one of the most commonly calculated attendance measures. While many educators assume a 95 percent ADA rate is an indicator of good attendance, our research found that is often not the case. We found that schools with average daily attendance rates higher than 97 percent rarely have a problem with chronic absence, but that schools with ADA rates between 93 and 97 percent need to analyze their data to determine whether chronic absence is a significant problem. Moreover, schools with ADA rates of 93 percent or below are almost certainly dealing with high concentrations of absenteeism. Local, state and federal governments can take steps to ensure districts and schools use existing data to monitor and identify chronic absence starting in kindergarten.