This paper is a practical guide (a toolkit) for researchers, students and practitioners wishing
to introduce randomization as part of a research design in the field. It first covers the …

People have a basic need to maintain the integrity of the self, a global sense of personal
adequacy. Events that threaten self-integrity arouse stress and self-protective defenses that …

There are fewer people living in extreme poverty in the world today than 30 years ago. While
that is an achievement, continuing progress for poor people is far from assured. Inequalities …

I combine a regression discontinuity design with rich data on academic and labor market
outcomes for a large sample of Florida students to estimate the returns to college admission …

Price dispersion across markets is common in developing countries. Using novel market and
trader-level data, this paper provides estimates of the impact of mobile phones on price …

The second edition of a comprehensive state-of-the-art graduate level text on
microeconometric methods, substantially revised and updated. The second edition of this …

Problems involving causal inference have dogged at the heels of statistics since its earliest
days. Correlation does not imply causation, and yet causal conclusions drawn from a …

Policy makers view public sector-sponsored employment and training programs and other
active labor market policies as tools for integrating the unemployed and economically …

This paper develops and applies semiparametric econometric methods to estimate the form
of selection bias that arises from using nonexperimental comparison groups to evaluate …

NBER WORKING PAPER SERIES THE PRODUCTIVITY ARGUMENT FOR INVESTING IN
YOUNG CHILDREN James J. Heckman Dimitriy V. Masterov Workin Page 1 NBER …