We begin by documenting the dramatic change over time in the academic characteristics of the students who have been entering charter schools. In table 4, we do so for sixth, seventh, and eighth graders by comparing the average prior-year test scores (and also the number of absences as a measure of student motivation) for students entering the charter school sector to those of students who stayed behind in traditional public schools for selected years.²⁰ Table 4 documents that the charter school sector has been attracting a relatively more able and motivated group of students over time. This trend is evident for both reading and math test scores in grades 6, 7, and 8. In each of the early years, the entering students were typically less able than their counterparts who remained in traditional public schools. In the more recent years, however, the situation changed quite dramatically. In these years, the average test scores of the new charter school students exceeded those of their former public school peers by more than 0.2 standard deviations in reading and about 0.15 standard deviations in math. Although we do not have data on student absences for the early years, the absence data for the later years indicates, consistent with their higher test scores, that the new entrants to charter schools had about 20 percent fewer absences, on average, than those who stayed behind, indicating higher student motivation and other cognitive skills that may lead to higher student outcomes.