On any given day, about 90% of USA students come to school — pretty good as attendance goes. But scratch beneath the surface and you may find less flattering figures. New research suggests that as many as 7.5 million students miss a month of school each year, raising the likelihood that they\'ll fail academically and eventually drop out of high school. The findings, from education researcher Robert Balfanz of Johns Hopkins University, estimate that 10% to 15% of students nationwide are \"chronically absent\" from school, missing enough class time to be at \"severe risk\" of dropping out. Among the biggest dilemmas, he says: Most states don\'t even measure how many kids miss more than a few days of school over the course of a year. Every parent gets individual kids\' absentee figures four times a year in their child\'s report card, but school districts seldom aggregate the data. As a result, Balfanz said, \"You can\'t get that data for your kid\'s school.\" Even schools with excellent attendance rates may have as many as one-in-four students missing more school than they should. For instance, a 500-student school in which 480 students show up each day can boast an excellent 96% attendance rate. But if each day a different group of 20 students is missing, it adds up quickly. If a school year is 180 days long, every student can miss seven days yet the school can still boast 96% attendance. \"What we\'re not measuring is, \'Who are those missing 20 kids?\' \" each day, he said. Balfanz, who has long researched the role that attendance and absenteeism play in urban education, found that just six states — Georgia, Florida, Maryland, Nebraska, Oregon and Rhode Island— track chronic absenteeism. He said the impact of all those missed school days is \"dramatic\" — students who miss a lot of school in one year are more likely to do the same in subsequent years. Over the course of four or five years they may miss more than half a school year. Among states that track long-term absenteeism, the figures are surprising: In Maryland, 61 high schools show 250 or more students missing at least one month of school each year. \"That\'s 10 classrooms of kids,\" Balfanz said. The new findings, out Thursday in conjunction with a congressional briefing, note that urban schools often have as many as one-third of students chronically absent. Balfanz is well-known in education circles for his research on what keeps kids in school — and what leads them to drop out. In 2007, he made waves by asserting that 1,700 USA high schools, about 12% of all high schools nationwide, were \"dropout factories,\" in which each senior class was comprised of fewer than 60% of the students who entered as freshmen. About half were in cities, Balfanz said, but the rest were scattered nationwide. In eight states, mostly concentrated in the South and West, \"dropout factories\" accounted for more than 20% of high schools. The new research was funded by the Get Schooled Foundation, an education non-profit funded by technology and entertainment companies, among others. It also has ties to the Bill & Melinda Gates Foundation, which has pushed to lower dropout rates nationwide.