Screen or Barrier? Science of Reading Certification Exams and Teacher Supply in Texas

Twenty states now require prospective teachers to pass a standalone Science of Reading (SOR) exam. These exams restrict teacher supply as a barrier, and whether they are worth that cost depends on whether they also screen on teaching quality. This paper explores this tension in Texas' SOR exam, required since 2021 for new elementary and middle-grades candidates, using administrative data linking exam attempts, certificates, employment, and student achievement. In a regression discontinuity at the passing threshold, narrowly failing lowers the probability of teaching the following year by 6.6 percentage points, driven by alternatively certified candidates. A difference-in-differences design comparing affected to unaffected certification fields within the same preparation programs shows that new certifications in affected fields surged ahead of implementation, then fell, and have not recovered five years later. Against these costs, exam scores predict student reading achievement more strongly than scores on the other certification exams candidates take, and students of teachers who passed on the first attempt score 0.024 standard deviations higher in reading than students of teachers who failed. The exam is thus a rare pre-hire predictor of teacher effectiveness, and lowering the threshold would likely admit less effective teachers. Structured Science of Reading coursework at preparation programs raised first-attempt pass rates about 4 percentage points, suggesting states can lower the barrier without lowering the standard.