This paper clarifies four areas of confusion about value-added methodology and its role in teacher evaluation: (1) use of value-added information; (2) consequences for teachers versus those for students of classifying and misclassifying teachers as effective or ineffective; (3) reliability of...

In his classic 1957 study of hybrid corn, Griliches emphasized the importance of economic incentives and profitability in the adoption of new technology, and this focus has been continued in the economics literature. But there is a distinct literature with roots in sociology emphasizing the...

This paper develops asymptotic distribution theory for instrumental variables regression when the partial correlations between the instruments and the endogenous variables are weak, here modeled as local to zero. Asymptotic representation are provided for various statistics, including two-stage...

This paper examines the precision of conventional estimates of the NAIRU and the role of the NAIRU and unemployment in forecasting inflation. The authors find that, although there is a clear empirical Phillips relation, the NAIRU is imprecisely estimated, forecasts of inflation are insensitive...

We examine the impact of increased abortion availability on the average living standards of children through a selection effect. Would the marginal child who was not born have grown up in different circumstances than the average child? We use variation in the timing of abortion legalization...

Abortion legalization in the early 1970s led to dramatic changes in fertility. Some research has suggested that it altered cohort outcomes, but this literature has been limited and controversial. In this paper, we provide a framework for understanding selection mechanisms and use that framework...

The authors investigate the effect of abortion access on teen birthrates using county-level panel data. Past research suggested that prohibiting abortion led to higher teen birthrates. Perhaps surprisingly, the authors find that more recent restrictions in abortion access, including the closing...