Community college students on academic probation who were required to take "college success" courses were more likely to return to good academic standing than were those who participated in a voluntary alternative, according to a new study by MDRC. The study examined a pair of programs at California's Chaffey College; an initial set of probationary students showed little academic gain after being offered participation in a voluntary program that gave them access to courses aimed at improving their reading, writing and math skills, but a subsequent group of students participating in a program in which they were required to attend the classes earned more academic credits and were likelier to earn a GPA of 2.0 than were students in a control group.