Patterns in Illinois educational school data

We examine Illinois educational data from standardized exams and analyze primary factors affecting the achievement of public school students. We focus on the simplest possible models: representation of data through visualizations and regressions on single variables. Exam scores are shown to depend on school type, location, and poverty concentration. For most schools in Illinois, student test scores decline linearly with poverty concentration. However, Chicago must be treated separately. Selective schools in Chicago, as well as some traditional and charter schools, deviate from this pattern based on poverty. For any poverty level, Chicago schools perform better than those in the rest of Illinois. Selective programs for gifted students show high performance at each grade level, most notably at the high school level, when compared to other Illinois school types. The case of Chicago charter schools is more complex. Up to 2008, Chicago charter and neighborhood schools had similar performance scores. In the last few years, charter students’ scores overtook those of students in traditional schools as the number of charter school locations increased.

Figure 1

(a) Percent of 11th graders at each Illinois school who passed the 2013 Math PSAE as a function of poverty concentration. The area of each point represents the number of test takers, and the color represents the percentage of minority students. (b) Same as (a) but excluding Chicago schools. It becomes particularly clear that Illinois school performance is very tightly correlated with poverty concentration and concentration of minority students.

Figure 2

(a) Percent of 11th graders at Chicago schools only who passed the 2013 Math PSAE as a function of poverty concentration. The size and color of the points represent the number of test takers and percent of minority students, respectively. (b) Chicago schools are again presented; in this case, symbols indicate the type of school as given in the table.

Figure 3

Illinois school performance, excluding Chicago schools, on the 2013 Math ISAT at grades 3 through 8. The area of each point represents the total number of students tested at each school, and the color represents the percentage of minority students in the school. Performance declines with increasing poverty concentration.

Figure 4

(a) Math performance scores of Chicago schools (blue) are compared to the fit to the data of other Illinois schools (red) at 8th and 11th grades. (b) Average differences of 2013 math exam performance at Chicago school programs when compared to other Illinois schools. The average difference $\mathrm{\Delta }$ of each school category is determined by $\mathrm{\Sigma }{N}_i[p_i-f_i(c_i)]/\mathrm{\Sigma }{N}_i$, where $p_i$ is the percent passing at each school, $f_i$ is the expected performance at that grade level (given in Table 2) based on the poverty concentration $c_i$ of the school, and $N_i$ is the number of students in each school of that category. The bars represent standard uncertainty. Table 3 gives the number of schools represented.

Figure 5

Average math ACT score of each Illinois school. (a) Math ACT score as a function of poverty concentration. The color of the points indicates the percent of minority students at each school. (b) School types are highlighted: Chicago charter schools, selective enrollment schools in Chicago, neighborhood schools in Chicago, and the rest of Illinois.

Figure 6

Percent of Chicago charter and traditional high school students and other Illinois school students who passed the math PSAE each year. There was a performance shift in 2009 among Chicago students after which a greater percent of charter students passed. Neighborhood schools have improved at about 1.5% per year from 2009 to 2013, compared to 0.8% per year among charter schools, as determined from the slopes of each fit. The table gives the number of schools and the number of students tested each year in those schools.