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The Vision for Baltimore RCT, evaluating a citywide program of free vision screening & eyeglasses in elementary & middle school, recently published results. Quick take: High-quality RCT finds no impact on English language arts (ELA) or math scores on the state test over 2 yrs.

Study Design:

  • The study sample comprised 127 elementary & middle schools, randomly assigned to get the program starting in 2016-7 schoolyear vs 2017-8 vs 2018-9. The study compared state test scores in ELA & math for students across the 3 groups who were screened as having vision problems.

  • Importantly, vision correction offers many benefits (e.g., quality of life, safety). This study sought to determine if such correction, as delivered by the Baltimore program, could also increase academic achievement in a student population that was 80-90% Black and low-income.


  • Unfortunately, the study found no significant impact on either ELA or math scores on the state test (the primary outcome), after either 1 year (based on 3,170 students) or 2 years (based on 1,528 students). The effect sizes were all close to zero.


  • Based on careful review, this was a mostly well-conducted RCT (e.g., low school & student attrition, good baseline balance, pre-specified analyses). Disclosure: Arnold Ventures (AV), my former employer, helped fund the study. Here's AV's summary.

  • The published study unfortunately doesn't make clear that the study's primary, pre-specified hypotheses were not supported, & instead highlights results (e.g., for subgroups) that are only exploratory & could be due to chance.

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