Instrumental Variables (IV) methods identify internally valid causal effects for individuals whose treatment status is manipulable by the instrument at hand. Inference for other populations requires some sort of homogeneity assumption. This paper outlines a theoretical framework that nests all...

What is the effect of trade on a country's environment, for a given level of GDP? Some have observed an apparent positive correlation between openness to trade and measures of environmental quality. But this could be due to endogeneity of trade, rather than causality. This paper uses exogenous...

Time series data are widely used to explore causal relationships, typically in a regression framework with lagged dependent variables. Regression-based causality tests rely on an array of functional form and distributional assumptions for valid causal inference. This paper develops a...

This essay reviews progress in empirical economics since Leamer's (1983) critique. Leamer highlighted the benefits of sensitivity analysis, a procedure in which researchers show how their results change with changes in specification or functional form. Sensitivity analysis has had a salutary but...

A longstanding question in the economics of the family is the relationship between sibship size and subsequent human capital formation and economic welfare. If there is a "quantity-quality trade-off," then policies that discourage large families should lead to increased human capital, higher...

This paper uses the 2000 Census 1-in-6 sample to look at the long-term impact of Vietnam-era military service. Instrumental Variables estimates using draft-lottery instruments show post-service earnings losses close to zero in 2000, in contrast with earlier results showing substantial earnings...

The veterans disability compensation (VDC) program, which provides a monthly stipend to disabled veterans, is the third largest American disability insurance program. Since the late 1990s, VDC growth has been driven primarily by an increase in claims from Vietnam veterans, raising concerns about...

We evaluate the effects of academic achievement awards for first and second-year college students on a Canadian commuter campus. The award scheme offered linear cash incentives for course grades above 70. Awards were paid every term. Program participants also had access to peer advising by...

High rates of attrition, delayed completion, and poor achievement are growing concerns at colleges and universities in North America. This paper reports on a randomized field experiment involving two strategies designed to improve these outcomes among first-year undergraduates at a large...

We analyze banking crises using a panel of macroeconomic and financial data for more than one hundred developing countries from 1975 through 1992. We find that banking crises in emerging markets are strongly associated with adverse external conditions. In particular Northern interest rates are...