A Think Twice Review of:

Urban Charter School Study

Think Twice - Apr 27, 2015

Publisher/Think Tank - Center for Research on Education Outcomes (CREDO) at Stanford University

Author(s) -

A recent report from the Center for Research on Education Outcomes (CREDO) at Stanford University attempted to investigate whether charter schools generate better outcomes than traditional public schools (TPS) in urban environments. The report, part of a series of reports on the performance of charter schools relative to TPS, asserts charter schools in urban environments provide a slightly greater test score advantage than those in non-urban environments. The report utilizes a methodological approach similar to previous reports from CREDO, and finds that students in urban charter schools were estimated to score approximately 0.055 standard deviations higher on math tests and 0.039 standard deviations higher on reading tests than their peers in urban TPSs.

Reviewer(s) - Andrew Maul, University of California Santa Barbara

An academic review issues concerns with the methodology and reporting of the CREDO study. In a review, Andrew Maul cites the following concerns: (1) the study’s “virtual twin” technique is insufficiently documented; (2) the report’s estimation of growth using “days of learning” requires accepting untested assumptions; and (3) the study includes a number of arbitrary and unexplained analytic choices. All the same, Maul states, “Even setting aside such concerns over analytic methods, the actual effect sizes reported are very small, explaining well under a tenth of one percent the variance in test scores.” In his conclusion, Maul says “The findings of this report cannot be regarded as compelling evidence of the greater effectiveness of charter school compared to traditional public schools, either overall or specifically within urban districts.”