The best and worst schools in NC last year

by Dr. Terry Stoops, The John Locke Foundation, September 11, 2015.

Last week, the N.C. Department of Public Instruction released student performance data for all schools and school districts in the state.  The release included school performance grades, end-of-course and end-of-grade achievement level results, school accountability growth data, the 4-year and 5-year cohort graduation rates, and a number of other metrics that give North Carolinians an imperfect but valuable estimation of the health of our public schools.

My preferred measure is school accountability growth or "value-added" data.  Value-added assessment is a measure of student growth from one point in time to another.  Naturally, we expect all students to attain at least a year's worth of academic growth through the course of each school year.  The Education Value-Added Assessment System (EVAAS) is a superb tool that predicts and measures academic growth based on the performance of each student on state standardized tests.

The major advantage of using EVAAS is that the characteristics of the student, including socioeconomic status, do not play a significant role in determining academic growth.  According to EVAAS developers at SAS, "EVAAS analyses show no correlation between students' growth and their socioeconomic status. Therefore, whether students are designated economically disadvantaged or not, they are equally likely to make good progress."  Thus, it is preferable to other measures, such as the school performance grades, that appear to be associated with differences in family income.

I examined EVAAS data for the 2014-15 school year and found schools with the lowest and highest growth indices (See Table 1 and 2).  Schools can meet growth expectations by earning a growth index of between -2 and +2.  Schools over +2 have exceeded their growth expectation.  Those below -2 have not met growth.  Alternative schools were excluded from the list.

Table 1. Highest Growth Schools, 2014-2015

The list of the top fifteen highest growth scores includes seven schools from Charlotte-Mecklenburg, two from Wake, and two from Carteret.  Interestingly, there is a sharp contrast between the two largest school districts in the state, Wake County and Charlotte-Mecklenburg.  The latter is clearly outperforming the former on EVAAS measures of student growth, despite the fact that Charlotte-Mecklenburg enrolls a much higher percentage of low-income students than Wake.

Table 2. Lowest Growth Schools, 2014-2015

On the other hand, school performance data suggests that the schools listed above have failed to deliver a sound, basic education to the children assigned to them. The list of the fifteen lowest growth scores includes three schools from Nash-Rocky Mount, three schools from Rowan-Salisbury, and two schools from Iredell-Statesville. Taxpayers, school board members, county commissioners, administrators, and teachers in these communities have some soul searching to do.

Accountability growth measures only capture particular state-administered grade and subject tests, including math, English Language Arts, and sometimes science.  It is possible that subjects not included, such as social studies, would show more promising growth trends.  It is also possible that this year's results are an anomaly for schools that experienced a change in district or school leadership.

Indeed, value-added data are not the last word.  The reasons why a school under- or out-performed its peers are best determined and addressed locally.  Only when a locality chooses to disregard or dismiss accountability results should taxpayers demand corrective action from state education officials, the legislature, or the courts.

Acronym of the Week

EVAAS -- Education Value-Added Assessment System

http://www.johnlocke.org/newsletters/research/2015-09-11-7mtc23ud0oes6m4g7poqre61q7-edu-update.html