In response to budget problems, many urban school systems reduced resources for getting students to come to school, such as truancy officers. Chicago, for instance, in 1991, went from 150 truancy officers down to a total of zero. Is that a good idea? In this study, we explore the effects of increased support by a pro-social adult, or "social capital," delivered through a structured student monitoring and mentoring program called Check & Connect (C&C). We carried out a large-scale randomized controlled trial with C&C in partnership with the Chicago Public Schools (CPS) to students in grades 1 to 8. Program participation decreased absences in grades 5 to 7 by 4.2 days, or 22.9 percent, but had no detectable effects on students in grades 1 to 4. We also did not find statistically significant effects on learning outcomes such as test scores or GPA, or any detectable spillovers to other students within the schools where the program was administered. The modest impacts per dollar spent, compared to previous evidence on either low-cost "nudges" or relatively intensive, higher-cost interventions, raise the possibility that, for very disadvantaged students, there may be decreasing returns that are then followed by increasing returns to program intensity for the problem of student disengagement.