A recent study by the Manhattan Institute's Jay Greene (High School Graduation Rates in the United States) shone a spotlight on the enormous number of students who disappear from school attendance rolls between 8th grade and 12th grade but aren't counted in any official dropout statistics. In a recent op-ed in The Houston Chronicle, Elena Vergara explains what happens to some of the thousands of eighth-graders in Houston who disappear before diplomas are awarded four years later. According to Vergara, there is a dramatic yearly enrollment surge between eight and ninth grade that can be traced back to a Texas law that prohibits students from failing more than one year each in elementary and middle school. Struggling students arrive in ninth grade by virtue of social promotion, not because they're ready to handle high school material. After failing their ninth-grade classes, an alarming percentage of these students drop out as soon as they turn 16 rather than repeat ninth grade. On the bright side, Vergara notes, social promotions are being phased out in Texas, and thanks to a new state law, school districts will begin reporting more accurate graduation and dropout statistics this school year. "HISD's 'ninth-grade bubble' deserves to burst," by Elena R. Vergara, The Houston Chronicle, December 7, 2001.