A major study from Stanford University recently found socioeconomic status was no indication of a given school's quality.

The truly important measure for school effectiveness was the rate at which students were making improvements on test scores.

The findings defy the typical assumptions about what makes a great public school.



For many parents, judging a local public school comes down to average test scores and the amount of money going into that school.

A new Stanford University study of test scores from 45 million students, who populate the about 11,000 US public-school districts, upends that set of assumptions.

The study found no correlation between a given district's socioeconomic status and the average test scores of its students. According to Stanford sociologist Sean Reardon, the smartest way to measure a school's effectiveness was to instead look at the students' rate of improvement over time, as measured by their standardized tests.

"There are many relatively high-poverty school districts where students appear to be learning at a faster rate than kids in other, less poor districts," Reardon said in a statement. "Poverty clearly does not determine the quality of a school system."

Reardon first gathered data on third-grade test scores, reasoning that kids performed roughly according to their family's level of wealth. "Affluent families and districts are able to provide much greater opportunities than poor ones early in children's lives," he wrote in the report.

Then he crunched the numbers on approximately 45 million test scores, from third- through eighth-graders in nearly every US school district. Surprisingly, Reardon found no correlation between how wealthy a district was and whether its kids were making outsized leaps in achievement.

In many cases, students in poor communities started with low test scores, but their scores rose much faster over the years than kids in wealthier areas. In high-poverty Chicago schools, for instance, students completed six years of material on average in just five years' time.

"Chicago students start out with low test scores in third grade, but their growth rate is much higher than the national average — 20% higher," Reardon said in a statement. "That is true for all racial and ethnic groups in the district."

The findings should help both parents and school districts, Reardon argued in his report.

Parents can use the information to better select schools for their kids. Instead of focusing on how high the test scores are or how big the school's budget is, they can focus on the test score improvement rate — the students' trajectory — to gauge whether a school is effective.

Districts can do their part by providing that information to parents, Reardon said. They can become better advocates for lower-income schools if those schools can boast high growth rates.

That argument in favor of public schools runs counter to much of what the Trump administration has sought to communicate over the past year — namely, that public schools are inefficient compared to a privatized model. Secretary of Education Betsy DeVos has compared school choice to picking between an Uber and a yellow cab.

Reardon wants to present a new way of thinking about schools based on the best available testing data.

"You might find parents ranking communities differently if they weren't relying on average test scores," he said in a statement, "which are highly correlated with socioeconomic background."