Do Low Levels of Blood Lead Reduce Children's Future Test Scores?

Abstract

We construct a unique individual-level dataset linking preschool blood lead levels with third grade test scores for Rhode Island children born 1997–2005. Using two identification strategies, we show for the first time that reductions of lead from even historically low levels have significant positive effects. A one-unit decrease in average blood lead levels reduces the probability of being substantially below proficient in reading (math) by 0.96 (0.79) percentage points on a baseline of 12 (16) percent. Since disadvantaged children have greater exposure to lead, lead poisoning may be one of the causes of continuing disparities in test scores.