From Joshua Angrist, winner of the Nobel Prize in Economics, and Jörn-Steffen Pischke, an irreverent guide to the essentials of econometrics The core methods in today's econometric toolkit are linear regression for statistical control, instrumental variables methods for the analysis of natural experiments, and differences-in-differences methods that exploit policy changes. In the modern experimentalist paradigm, these techniques address clear causal questions such as: Do smaller classes increase learning? Should wife batterers be arrested? How much does education raise wages? Mostly Harmless Econometrics shows how the basic tools of applied econometrics allow the data to speak. In addition to econometric essentials, Mostly Harmless Econometrics covers important new extensions—regression-discontinuity designs and quantile regression—as well as how to get standard errors right. Joshua Angrist and Jörn-Steffen Pischke explain why fancier econometric techniques are typically unnecessary and even dangerous. The applied econometric methods emphasized in this book are easy to use and relevant for many areas of contemporary social science. An irreverent review of econometric essentials A focus on tools that applied researchers use most Chapters on regression-discontinuity designs, quantile regression, and standard errors Many empirical examples A clear and concise resource with wide applications

From Joshua Angrist, winner of the Nobel Prize in Economics, and Jörn-Steffen Pischke, an accessible and fun guide to the essential tools of econometric research Applied econometrics, known to aficionados as 'metrics, is the original data science. 'Metrics encompasses the statistical methods economists use to untangle cause and effect in human affairs. Through accessible discussion and with a dose of kung fu–themed humor, Mastering 'Metrics presents the essential tools of econometric research and demonstrates why econometrics is exciting and useful. The five most valuable econometric methods, or what the authors call the Furious Five—random assignment, regression, instrumental variables, regression discontinuity designs, and differences in differences—are illustrated through well-crafted real-world examples (vetted for awesomeness by Kung Fu Panda's Jade Palace). Does health insurance make you healthier? Randomized experiments provide answers. Are expensive private colleges and selective public high schools better than more pedestrian institutions? Regression analysis and a regression discontinuity design reveal the surprising truth. When private banks teeter, and depositors take their money and run, should central banks step in to save them? Differences-in-differences analysis of a Depression-era banking crisis offers a response. Could arresting O. J. Simpson have saved his ex-wife's life? Instrumental variables methods instruct law enforcement authorities in how best to respond to domestic abuse. Wielding econometric tools with skill and confidence, Mastering 'Metrics uses data and statistics to illuminate the path from cause to effect. Shows why econometrics is important Explains econometric research through humorous and accessible discussion Outlines empirical methods central to modern econometric practice Works through interesting and relevant real-world examples

Applied econometrics, known to aficionados as 'metrics, is the original data science. 'Metrics encompasses the statistical methods economists use to untangle cause and effect in human affairs. Through accessible discussion and with a dose of kung fu-themed humor, Mastering 'Metrics presents the essential tools of econometric research and demonstrates why econometrics is exciting and useful. The five most valuable econometric methods, or what the authors call the Furious Five--random assignment, regression, instrumental variables, regression discontinuity designs, and differences in differences-

The education reform movement includes efforts to raise teacher quality through stricter certification and licensing provisions. Most US states now require public school teachers to pass a standardized test such as the National Teacher Examination. Although any barrier to entry is likely to raise wages in the affected occupation, the theoretical effects of such requirements on teacher quality are ambiguous. Teacher testing places a floor on whatever skills are measured by the required test, but testing is also costly for applicants. These costs shift teacher supply to the left and may be especially likely to deter high-quality applicants from teaching in the public schools. We use the Schools and Staffing Survey to estimate the effect of state teacher testing requirements on teacher wages and teacher quality as measured by educational background. The results suggest that state-mandated teacher testing increases teacher wages with no corresponding increase in quality.

The majority of armed forces veterans make use of the subsidized training and educational benefits provided by the Department of Veterans Affairs. The effect of veterans benefits on educational attainment am civilian earnings is estimated here using the Census Bureau's 1987 Survey of Veterans. Two identification strategies are employed to control for unobserved characteristics that are correlated with educational attainment and benefit usage. First, a fixed effects strategy is implemented by exploiting information on educational attainment at the time of entry to service. Second, instrumental variables estimates are computed, where the excluded instruments are interactions between period of service am educational attainment at entry to service. The effect of veterans benefits on earnings is estimated by decomposing the return to education into a return to the grade completed at entry to service and a return to the post-entry grade increment. Veterans benefits are estimated to increase schooling by roughly 1.4 years and the grade increment is worth roughly 4.3 percent, so that veterans benefits raise annual earnings by approximately 6 percent. This premium appears to accrue primarily to the 77 percent of benefit users who attended college or graduate school.

Applied economists have long struggled with the question of how to accommodate binary endogenous regressors in models with binary and non-negative outcomes. I argue here that much of the difficulty with limited-dependent variables comes from a focus on structural parameters, such as index coefficients, instead of causal effects. Once the object of estimation is taken to be the causal effect of treatment, a number of simple strategies is available. These include conventional two-stage least squares, multiplicative models for conditional means, linear approximation of nonlinear causal models, models for distribution effects, and quantile regression with an endogenous binary regressor. The estimation strategies discussed in the paper are illustrated by using multiple births to estimate the effect of childbearing on employment status and hours of work.

A combination of voluntary enlistment, armed forces eligibility criteria, and the failure of draftees to avoid conscription jointly determined the racial composition of the Vietnam-era armed forces. Administrative data show that men with draft lottery numbers that put them at high risk of conscription are overrepresented among men who voluntarily enlisted in the military, but that the effect of the lottery on enlistment is stronger for whites than for nonwhites. Minimum Chi-Square estimates of enlistment models for the 1971 draft lottery suggest that nonwhites were more likely than whites to prefer enlistment to a civilian career. This finding appears to explain racial differences in the effect of the lottery on enlistment. Contrary to the findings of a recent congressional study, the Vietnam-era estimates presented here suggest that conscription of a relatively small number of whites and nonwhites in a manner proportional to their prevalence in the population might substantially reduce nonwhite representation in the armed forces.

La econometría aplicada es la ciencia de los datos en su estado original, y engloba los métodos estadísticos que se usan en economía para desentrañar causas y efectos de las actividades humanas. Con un lenguaje accesible y algunas dosis de humor con sabor a kung-fu, esta obra expone las herramientas esenciales del análisis econométrico y desvela por qué la econometría es una disciplina tan apasionante y útil. ¿Mejoran la salud los seguros médicos? ¿Son mejores las universidades de élite que otro tipo de centros académicos? Cuando la banca privada se tambalea, y los inversores toman el dinero y huyen, ¿deben acudir en su ayuda los bancos centrales? Angrist y Pischke nos muestran que, con los métodos adecuados, la econometría es capaz de ofrecernos respuestas a preguntas tan dispares como estas. "Esta obra, escrita por verdaderos maestros de la econometría, es perfecta para quienes deseen estudiar esta materia crucial." (Hal Varian, economista jefe de Google)