Families originally living in public housing were assigned housing vouchers by lottery,
encouraging moves to neighborhoods with lower poverty rates. Although we had hypothesized
that reading and math test scores would be higher among children in families offered vouchers
(with larger effects among younger children), the results show no significant effects on test
scores for any age group among over 5000 children ages 6 to 20 in 2002 who were assessed four
to seven years after randomization. Program impacts on school environments were considerably
smaller than impacts on neighborhoods, suggesting that achievement-related benefits from
improved neighborhood environments are small.
social experiments
Several important social science literatures hinge on the functional relationship between
neighborhood characteristics and individual outcomes. Although there have been numerous
non-experimental estimates of these relationships, there are serious concerns about their
reliability because individuals self-select into neighborhoods. This paper uses data from HUD’s
Moving to Opportunity (MTO) randomized housing voucher experiment to estimate the
relationship between neighborhood poverty and individual outcomes using experimental
variation. In addition, it assesses the reliability of non-experimental estimates by comparing
them to experimental estimates.
We find that our method for using experimental variation to estimate the relationship
between neighborhood poverty and individual outcomes – instrumenting for neighborhood
poverty with site-by-treatment group interactions – produces precise estimates in models in
which poverty enters linearly. Our estimates of nonlinear and threshold models are not precise
enough to be conclusive, though many of our point estimates suggest little, if any, deviation from
linearity. Our non-experimental estimates are inconsistent with our experimental estimates,
suggesting that non-experimental estimates are not reliable. Moreover, the selection pattern that
reconciles the experimental and non-experimental results is complex, suggesting that common
assumptions about the direction of bias in non-experimental estimates may be incorrect.