From the report: "Participation in the program was low: only 25% of the students who had not completed at least 70% of their assignments by the end of the spring term—and thus expected to attend summer school—actually participated. In contrast, over 5,000 students who were not required to attend summer school chose to participate. ● Along most dimensions, the average observable characteristics of summer school participants and non-participants are similar. Two notable differences include race and assignment completion rates. Participants were more likely to be Asian and less likely to be White or Hispanic relative to nonparticipants. Among all participants, average spring semester assignment completion rates were lower than those of non-participants. On average, summer school participants experienced a one-half month gain in math achievement growth and a one-fourth month reduction in reading achievement growth relative to non-participants. The difference in reading scores, however, was not statistically significant."