The more a student misses class, the more likely he is to fail the course. The more courses she fails, the less likely she is to graduate on time. But freshmen don’t know those equations. In spring 2004, 49 percent of freshmen missed more than two weeks of school in a major subject, according to research by the Consortium on Chicago School Research. Some were officially absent, but others were simply cutting class. Schools have few resources to solve this problem.