When properly considered, Kansas often underperforms the nation in the most recent assessment of “The Nation’s Report Card.”
The results for the 2017 administration of the National Assessment of Educational Progress, or NAEP, were recently released. I’ve prepared interactive visualizations of some of the results. To access the visualizations, click on National Assessment of Educational Progress (NAEP).
When considering NAEP results, it’s important to consider subgroups, such as race/ethnicity and school lunch status, which is a proxy for poverty. It’s important because states vary widely in the composition of subgroups.
For example, consider an accompanying example from the visualization. We see that when considering all students, Kansas does better than the national average in percent of students performing as basic or better. This is true in all four combinations of grade and subject.
Looking at black students alone, however, we see that Kansas underperforms the nation, except in one instance where there is a tie.
For Hispanic students alone, Kansas does better in all instances except for one tie.
For white students alone, Kansas underperforms the nation in three instances, and outperforms in one.
This statistical anomaly is known as Simpson’s Paradox. It may appear when comparing subgroups to aggregated data when the proportional composition of subgroups varies between populations, in this case the states. For grade 4 reading, 64 percent of students in Kansas were white. For the nation, it was 49 percent. This is a difference in composition that must not be ignored.
The relatively low proportion of minority students is why Kansas appears to perform better than the nation. The apparent superior performance of Kansas melts away when looking at subgroups.