A constant refrain in the wake of the recent report by the National Research Council (NRC) on mayoral control of DC public schools (the 2007 PERAA law) is problems with data.

But really, it’s the public that is the problem. As in: the educational data DC residents get (or not) for their tax investment in local schools.

For instance, the NRC report cited lack of data on teachers and learning conditions in DC charter schools such that it could evaluate neither because no information was collected systematically. The report also noted that even when there is data, it may not be public or may exist in uncoordinated websites, so that public access is effectively barred.

None of this is a stellar conclusion for what amounts to over $1 billion spent annually on DC public education–most of it directly from DC taxpayers.

And then there is the data that does not apparently exist, as state board of education member Ruth Wattenberg pointed out in a recent Post editorial. That includes data on teacher retention by school; data on the time taken every year simply for standardized testing; and data on how much our kids are learning (not test scores).

The problem is compounded by the fact that not everyone with access to DC education data is even located in DC.

As retired teacher and schools advocate Erich Martel discovered when he FOIA’ed it, the Walton Family Foundation signed an agreement with DCPS in 2011 to get detailed data on student enrollment and performance for a period of 10 years, including scale scores and raw scores. (The foundation also signed an agreement through OSSE for similar data for charter schools.) The foundation appears to want to leverage its investment in public schools here.

So: how do DC taxpayers get data to leverage our much larger investment in our own schools?

Among the recommendations of the NRC report was the creation of an educational data warehouse that would be “available in one place that is readily accessible online to parents, the community, and researchers.”

A few years back, Code for DC used data from OSSE (DC’s state superintendent of education) to create a clever mapping tool showing where kids who attend each DC school live. But the tool is not entirely current because it is done by volunteers, not by those paid to collect the data.

One math teacher at Dunbar High would take this all a lot further.

In June, in testimony at a council hearing on the NRC report, David Tansey said that any education database should not be centered on individual school data—as most DC school performance data is now collected and disseminated. (Case in point: the unified lottery website MySchoolDC, which provides test score data for each school as a point of comparison.)

Rather, Tansey noted, a rich database would use a per pupil longitudinal tool that tracks individual kids throughout their time as DC public school students. That would determine where students go in our highly mobile environment of school choice, allowing easier identification of effective programming and city-wide patterns, such as mid-year transfers that have negative effects on both schools and student performance.

Such a student-centric database would also help address persistent concentrations of high-risk students in a subset of schools, one artifact of largely homogenous school populations in DC.

This issue is not merely one of diversity. Research shows that poor children do worse in schools with large concentrations of poverty.

And this is intimately related to test score reporting: In his testimony, Tansey noted how school test scores are correlated to household income (and at risk status) of the students attending, such that schools become ranked “by who they teach rather than how well they serve the needs of the city’s population.”

(Tansey is not alone in noting that test scores miss, or at least obscure, achievement. Last year, assessing achievement in DC schools, an Urban Institute researcher determined that the “best measure of school quality is how much students learn,” not test scores.)

This fall, according to the council’s education committee report on the NRC hearing, the deputy mayor for education “will be launching a data resource page to support planning.” The idea, the committee report states, is “sharing cross sector data with the public in an effort to better understand the education landscape in the city.”

Data matters—and who has access to it matters just as much.