The second edition of this acclaimed graduate text provides a unified treatment of two methods used in contemporary econometric research, cross section and data panel methods. By focusing on assumptions that can be given behavioral content, the book maintains an appropriate level of rigor while emphasizing intuitive thinking. The analysis covers both linear and nonlinear models, including models with dynamics and/or individual heterogeneity. In addition to general estimation frameworks (particular methods of moments and maximum likelihood), specific linear and nonlinear methods are covered in detail, including probit and logit models and their multivariate, Tobit models, models for count data, censored and missing data schemes, causal (or treatment) effects, and duration analysis. Econometric Analysis of Cross Section and Panel Data was the first graduate econometrics text to focus on microeconomic data structures, allowing assumptions to be separated into population and sampling assumptions. This second edition has been substantially updated and revised. Improvements include a broader class of models for missing data problems; more detailed treatment of cluster problems, an important topic for empirical researchers; expanded discussion of "generalized instrumental variables" (GIV) estimation; new coverage (based on the author's own recent research) of inverse probability weighting; a more complete framework for estimating treatment effects with panel data, and a firmly established link between econometric approaches to nonlinear panel data and the "generalized estimating equation" literature popular in statistics and other fields. New attention is given to explaining when particular econometric methods can be applied; the goal is not only to tell readers what does work, but why certain "obvious" procedures do not. The numerous included exercises, both theoretical and computer-based, allow the reader to extend methods covered in the text and discover new insights.

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Econometric Analysis of Cross Section and Panel Data

Most papers that employ Differences-in-Differences estimation (DD) use many years of data and focus on serially correlated outcomes but ignore that the resulting standard errors are inconsistent. To illustrate the severity of this issue, we randomly generate placebo laws in state-level data on female wages from the Current Population Survey. For each law, we use OLS to compute the DD estimate of its “effect” as well as the standard error of this estimate. These conventional DD standard errors severely understate the standard deviation of the estimators: we find an “effect” significant at the 5 percent level for up to 45 percent of the placebo interventions. We use Monte Carlo simulations to investigate how well existing methods help solve this problem. Econometric corrections that place a specific parametric form on the time-series process do not perform well. Bootstrap (taking into account the autocorrelation of the data) works well when the number of states is large enough. Two corrections based on asymptotic approximation of the variance-covariance matrix work well for moderate numbers of states and one correction that collapses the time series information into a “pre”- and “post”-period and explicitly takes into account the effective sample size works well even for small numbers of states.

/pdf/how-much-should-we-trust-differences-in-differences-407p70a9b4.pdf

How Much Should We Trust Differences-In-Differences Estimates?

https://www.oxfordmartin.ox.ac.uk/downloads/academic/The_Future_of_Employment.pdf

The future of employment: How susceptible are jobs to computerisation?

This paper examines the reflection problem that arises when a researcher observing the distribution of behaviour in a population tries to infer whether the average behaviour in some group influences the behaviour of the individuals that comprise the group. It is found that inference is not possible unless the researcher has prior information specifying the compisition of reference groups. If this information is available, the prospects for inference depend critically on the population relationship between the variables defining reference groups and those directly affecting outcomes. Inference is difficult to implossible if these variables are functionally dependent or are statistically independent. The prospects are better if the variables defining reference groups and those directly affecting outcomes are moderately related in the population.

/pdf/identification-of-endogenous-social-effects-the-reflection-rurdh6yhqn.pdf

Identification of Endogenous Social Effects: The Reflection Problem

▪ Abstract This paper assesses and synthesizes the cumulative results of a new “neighborhood-effects” literature that examines social processes related to problem behaviors and health-related outcomes. Our review identified over 40 relevant studies published in peer-reviewed journals from the mid-1990s to 2001, the take-off point for an increasing level of interest in neighborhood effects. Moving beyond traditional characteristics such as concentrated poverty, we evaluate the salience of social-interactional and institutional mechanisms hypothesized to account for neighborhood-level variations in a variety of phenomena (e.g., delinquency, violence, depression, high-risk behavior), especially among adolescents. We highlight neighborhood ties, social control, mutual trust, institutional resources, disorder, and routine activity patterns. We also discuss a set of thorny methodological problems that plague the study of neighborhood effects, with special attention to selection bias. We conclude with promising ...

ASSESSING "NEIGHBORHOOD EFFECTS": Social Processes and New Directions in Research

The For-Profit Postsecondary School Sector: Nimble Critters or Agile Predators? NBER Working Paper No. 17710.

Antipoverty policies may hold promise as tools to improve health and reduce mortality rates among low-income Americans. We examined the health effects of the New York City Paycheck Plus randomized controlled trial. Paycheck Plus tests the impact of a potential fourfold increase in the Earned Income Tax Credit for low-income Americans without dependent children. Starting in 2015, Paycheck Plus offered 5,968 study participants a credit of up to $2,000 at tax time (treatment) or the standard credit of about $500 (control). Health-related quality of life and other outcomes for a representative subset of these participants (n = 3,289) were compared to those of a control group thirty-two months after randomization. The intervention had a modest positive effect on employment and earnings, particularly among women. It had no effect on health-related quality of life for the overall sample, but women realized significant improvements.

The Health Effects Of Expanding The Earned Income Tax Credit: Results From New York City

Pharmacy has become a female-majority profession that is highly remunerated with a small gender earnings gap and low earnings dispersion relative to other occupations. We sketch a labor market framework based on the theory of equalizing differences to integrate and interpret our empirical findings on earnings, hours of work, and the part-time work wage penalty for pharmacists. Using extensive surveys of pharmacists for 2000, 2004, and 2009 as well as samples from the American Community Surveys and the Current Population Surveys, we explore the gender earnings gap, the penalty to part-time work, labor force persistence, and the demographics of pharmacists relative to other college graduates. We address why the substantial entrance of women into the profession was associated with an increase in their earnings relative to male pharmacists. We conclude that the changing nature of pharmacy employment with the growth of large national pharmacy chains and hospitals and the related decline of independent pharmacies played key roles in the creation of a more family-friendly, female-friendly pharmacy profession. The position of pharmacist is probably the most egalitarian of all U.S. professions today.

https://papers.ssrn.com/sol3/Delivery.cfm/nber_w18410.pdf?abstractid=2150541&mirid=1&type=2

The Most Egalitarian of All Professions: Pharmacy and the Evolution of a Family-Friendly Occupation

In his seminal analysis of the economics of crime, Gary Becker (1968) pointed out that the cost of achieving any given degree of deterrence is minimized by combining an infinitesimal probability of detection and an arbitrarily large punishment. In Kolm’s (1973) phrase, an optimizing government ‘should hang tax evaders with probability zero’. While Becker’s observation is a correct assertion about how crime can be deterred at lowest cost, it is wildly inaccurate as a positive theory of government law enforcement activities. Governments typically spend significant amounts on the detection of crime.

Why Do Firms Monitor Workers

In the three decades from 1910 to 1940, the fraction of U.S. youths enrolled in public and private secondary schools increased from 18 to 71 percent and the fraction graduating soared from 9 to 51 percent. At the same time, state compulsory education and child labor legislation became more stringent and potentially constrained secondary-school aged youths. It might appear from the timing and the specifics of this history that the laws caused the increase in education rates. We evaluate the possibility that state compulsory schooling and child labor laws caused the increase in education rates by using contemporaneous evidence on enrollments. We also use micro-data from the 1960 census to examine the effect of the laws on overall educational attainment. Our estimation approach exploits cross-state differences in the timing of changes in state laws. We find that the expansion of state compulsory schooling and child labor laws from 1910 to 1939 can, at best, account for 5 percent of the increase in high school enrollments and can account for about the same portion of the increase in the eventual educational attainment for the affected cohorts over the period.

Lawrence F. Katz

Papers

The For-Profit Postsecondary School Sector: Nimble Critters or Agile Predators? NBER Working Paper No. 17710.

The Health Effects Of Expanding The Earned Income Tax Credit: Results From New York City

The Most Egalitarian of All Professions: Pharmacy and the Evolution of a Family-Friendly Occupation

Why Do Firms Monitor Workers

Mass Secondary Schooling and the State: The Role of State Compulsion in the High School Movement