How to make the data work for us
Let’s grade schools on the basis of a school’s poverty level.
Sure, it’s a dumb idea, but it leads to the same result as the North Carolina school grades that came out on Feb. 5.
Here I show the connection between school performance and poverty levels using the composite scores underlying the grades.
Using the data from the N.C. Department of Public Instruction website, I plot the fraction of a school’s students getting free lunches on the horizontal axis, and the composite scores on the vertical axis.
The composite score combines student achievement scores and school growth scores in an 80-20 weighting, and the plot shows points for the 2,272 schools that had all the numbers.
These scores were turned into the reported letter grades: A=85-100, B=70-85, C=55-70, D=40-55, and F is below 40.
It’s pretty clear that schools with high free-lunch fractions got poor scores and poor grades. A school with all its student getting free lunches had half the performance of a high-wealth school.
More than half of each school’s composite score is explained by a school’s free lunch fraction. More than 60 percent of a school’s average student achievement is explained by a school’s free-lunch fraction.
Certainly we could blame teachers and administrators for their students’ parents’ income level, but, perhaps, the more rational and productive approach would be to recognize the difficulties of growing up poor in North Carolina. Poverty leads to challenges that exist beyond our schools, and we need to address poverty issues if we hope to improve student scores in the classroom.
Data like these could be very helpful. A straight line drawn along the free lunch axis from performance values of 100 to 50 identify above-average schools (above the line). In particular, we could identify high-poverty schools with performance scores above, say, 60, and find out what they’re doing right with the students they serve and try to replicate those performances elsewhere.
In contrast, for low-poverty schools with performances below 80, we can ask, what’s the problem?