The Secret Behind the Best School Performance Scores

Part I: A look at the data relating school performance scores and school letter grades to the rate of family poverty in Louisiana public schools

It took 3 successful public records lawsuits against the Louisiana Department of Education and the successful defense of a 4th lawsuit against me by the LDOE to get the accurate data that can be used to compare school performance scores to family poverty in each public school district. Now any person interested in the possible effect of poverty on school performance can view the results of this comparison.

The following chart was created by my son Donny, who is a graduate of the LSU school of business and who holds an MBA degree from Mississippi State. Donny majored in Quantitative Business Analysis and does statistical analysis for one of the largest companies in Baton Rouge. It turns out his skills can be applied to analyze our Louisiana public education data.

The graph below compares poverty of families of children enrolled in each school district in 2016 to average School Performance Scores (SPS). Poverty is determined by the percentage of families qualifying for free or reduced lunch or a comparable measure of wealth. The correlation coefficient comparing school performance to poverty is -0.826. The negative sign indicates an inverse or opposite correlation of school performance to the percentage of families that are economically disadvantaged. This relation is very statistically strong.

The  Excel chart below is a ranking of all public school districts in Louisiana based on poverty. The ranking starts with the school systems serving the smallest percentage of students living in poverty. This ranking is the data that was used to produce the graph shown above. Notice that even though the ranking is not a ranking by school performance scores, it ends up being almost the same. That's because of the strong correlation of family poverty based on free or reduced priced lunch to school performance. (Note: The gap in the chart is simply a page break.)

The school districts near the top of the chart are those with the smallest percentage of families struggling with poverty. Note that they are also the school districts with the top letter grades. These rankings demonstrate an uncanny relation between school performance and poverty in Louisiana. The smaller percentage of families living in poverty is the secret behind the best school performance scores!

I believe this data calls into question Louisiana's policy of grading public schools without considering the negative effects of poverty on SPS and therefore school grades. Apparently all we are doing is grading our schools based on the poverty of their students. What is the purpose of a system that classifies community schools as failing just because they happen to serve a large percentage of students that are struggling with poverty?

Think about it. Is this a fair way of rating our schools?

Part II will look at specific cases of school performance and examine the unintended consequences of our obsession with rating and grading schools using test score results.

Michael Deshotels