Before revision:  These findings are illustrated using data from a conditional cash transfer program and with simulations  .
After revision:  These findings are illustrated using data from a conditional cash transfer program and with simulations . The empirical results reveal the potential pitfalls of failing to flexibly account for spillover effects in policy evaluation: the estimated difference in means and the LIM coefficients are all close to zero and statistically insignificant, whereas the nonparametric estimators I propose reveal large, nonlinear and significant spillover effects .