The relationship between early achievement and subsequent gains is not weak because districts consistently maintain inequality that is brought to their doorstep, but because different school districts have different impacts on student gains.

Do schools reduce, replicate, or exacerbate inequality?

A recent report says “yes”

Yesterday the 2017 National Assessment of Educational Progress (NAEP) data were released, reflecting reading and math test scores of hundreds of thousands of fourth and eighth graders. Although the nationwide results show gradually improving scores over the quarter century since the tests were established, the major takeaway from this year’s math and reading tests seem to be “no changes.”

For some, that sort of headline will reinforce their beliefs that America’s educational systems are broken. But are they? More specifically, are our schools meeting their lofty goals of providing all children with their best opportunity to succeed?

The answer to those questions might well be -0.13.

That figure is the “correlation coefficient” between the achievement test scores of millions of third graders, and the growth of their scores over the ensuing five years, according to a recent study from Stanford’s Center for Education Policy Analysis (CEPA).

Correlation coefficients range from -1 to 1, and those closer to zero, like -0.13, generally signal weak relationships. In this case, the weak correlation means that third graders in districts with high average reading and math test scores will not necessarily see bigger (or smaller) gains by eighth grade than will third graders in lower-scoring districts.

If your belief is that the school system exacerbates inequality—that the advantaged districts that start with high achievers strongly accelerate the educational growth of their students, whereas students of lower-achieving, disadvantaged districts are destined to meager growth—you might have guessed that such a correlation would be strong and positive.
If you believe that schools function as a great equalizer, you might have expected a stronger negative relationship.
If you believe in the remaining option, however, that school systems consistently mirror the inequality occurring outside of school doors, that is not quite right either.

The relationship between early achievement and subsequent gains is not weak because districts consistently maintain inequality that is brought to their doorstep, but because school districts’ impacts on student gains are inconsistent. As the study’s author, Dr. Sean Reardon, states, “the role of schooling in shaping educational opportunity varies substantially across places.”

In other words, the answer to the question of whether school districts decrease, replicate, or increase inequality is “Yes.” Or, more precisely, it depends on which district you are talking about.

Average test score growth rates (math and reading averaged), U.S. public school districts, 2009-2015

Note: Darkest green areas showed greatest growth, while darkest purple areas showed the least growth. Source: CEPA Working Paper No. 17-12. Data Source: Stanford Education Data Archive (Reardon et al. 2017a), page 37.

At the same time, the findings of Reardon and his colleagues at CEPA clearly demonstrate the enduring influence of social and economic factors that reach far beyond classroom walls on student outcomes.

Nationally, third graders of poor school districts already lag 1.5 years behind “non-poor” districts, and of the four racial and ethnic groups included in the study (Asian, Black, Hispanic, White) the average third grade test scores of the highest group (Asian) reflects more than two years of academic progress beyond the group with the lowest average (Black). Those gaps are particularly discouraging given that even the most effective school districts are only able to help their third graders achieve one extra year of growth by eighth grade.

With findings like these, the research agenda of Reardon and his CEPA colleagues merits attention. Their work underscores the importance of using student growth rates (versus more typically referenced point-in-time proficiency levels) to evaluate school system performance.

Additionally, their ground-breaking data set, which transforms results from millions of achievement tests previously not comparable across state lines into a directly comparable national standard based in part on the NAEP, is available for public use.

This data set is a powerful platform for identifying districts that appear strongest in propelling student learning. Researchers and educators likely will be mining this data for years to come. The New York Times has already used it to create a great on-line interactive that highlights the Chicago Public Schools as one of the nation’s strongest growth districts—and allows you to see how your district compares.

-Craig (@c_helmstetter)

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