PERHAPS the most notorious school-skippers, real or fictional, are Huck Finn and Tom Sawyer--characters brought into being by their similarly adventure-seeking creator, Samuel Clemens, or Mark Twain. Tom and Huck (and Twain) were all about escape and freedom. When Huckleberry Finn went to live with the Widow Douglas, she took him for a son and allowed she would sivilize him. We all know how successful she was. Huck could not be sivilized. All he wanted to do was head out for a smoke and get out of his rigid, confining clothes. Huck has never been alone in wanting to live free. There have always been many like him, and that is why we have compulsory education laws. Early civilized communities recognized that the only way to keep students in school up to a certain age was to them go. (Massachusetts was the first, in 1852, to mandate compulsory attendance for children between the ages of 8 and 14.) Compulsory attendance laws specify the age for starting school and the age at which students may follow Huck outdoors for adventure without getting dragged back in by the ear. In doing so, these laws not only the kids go to school, but put pressure on parents to get them there. PRESSURES FOR CHANGE Since A Nation at Risk came out in 1983, an increasing number of lawmakers have attempted to curb the adventures of young people by raising the age at which students may leave school. In 1960, four states set the age at 18. That number had increased to just five by 1970, but by the end of 2006, 16 states required students to attend school until the age of 18 or graduation, whichever comes first. (For a look at compulsory schooling laws in all the states, visit www.ecs.org/clearinghouse/64/07/6407.pdf.) Today, perhaps the greatest pressure to keep kids in school longer is coming from the No Child Left Behind Act. NCLB establishes graduation rates as one of the measures that determine whether a school makes adequate yearly progress. While each state sets its own graduation rate target, the law holds schools accountable for meeting that state-set target. This in turn puts on pressure to sure students graduate. They can't graduate if they don't attend, and many won't attend unless we make 'em. DO THESE LAWS WORK? Critics say that forcing students to attend school is counterproductive, that students who don't want to be there often become disruptive influences. They claim that it's more important for schools to improve the educational experience for students who are disengaged or so far behind their peers that they cannot see a way to catch up. For too many students, the light has gone out, and they see no reason to attend. A system of credits based on seat time, or Carnegie Units, does not lend itself to helping students up for time lost during months or years of adolescent disengagement. Proponents say that raising the compulsory attendance age decreases dropout rates, juvenile crime, and teen pregnancy, while it produces graduates who--because they hold at least a high school diploma--can earn higher wages over the course of their lifetimes. In 1990 the National Bureau of Economic Research (NBER) published a little-known study that estimated that 25% of potential dropouts remain in school because of compulsory schooling laws. The authors based that estimate on Census Bureau data rather than on state- or school-provided calculations of the dropout rate (or graduation rate). Readers are no doubt familiar with current literature that suggests that state, district, and school calculations lack credibility. Once high-quality student information systems are in place everywhere, we'll have better data. Meanwhile, though NBER's estimates are somewhat dated, such data are at least based on credible measures. RECENT STATE ACTIVITY Every year, a few state legislatures address the issue of compulsory school age. In the 2006 session, Tennessee changed its compulsory attendance age from 7 to 16, to 6 to 17. …