While just about all students miss school some days during their elementary and secondary years for occasional sickness and family needs, some students miss school far more often. One conservative estimate is that 10 percent of students miss at least 10 percent of school days each year. On top of being counted as absent for the full day, many students skip classes even when they are officially in school. In fact, students are as likely to miss a class because they simply choose to skip than they are to miss because they are out for the day. As shown in Figure below, students’ unexcused class absence rate, on days they attend at some point, doubles once they enter high school (at least in this urban school district). Moreover, unexcused class absences on days when students are in school explains almost all of the increase in total absences in high school.
Missing school and skipping class is consequential. Using variation in attendance caused by inclement weather, one study estimated that each additional absence reduced math achievement by 0.05 standard deviations, suggesting that attendance can account for up to one-fourth of the achievement gap by income. A similar study using data on students in Philadelphia found that living farther from school increased absences and resulted in lower grade point averages and test scores.