Thousands of D.C. middle school students will be paid up to $100 every two weeks for attending school, staying out of trouble and getting good grades under a new program meant to inspire achievement with cash.

About 3,000 sixth-, seventh- and eighth-graders from 14 of the District’s 28 middle schools will participate in what officials are calling “Capital Gains,” an alliance between D.C. Public Schools and Harvard University’s American Inequality Lab.