This paper considers a dynamic model of the evolution of open source software projects, focusing on the evolution of quality, contributing programmers, and users who contribute customer support to other users. Programmers who have used open source software are motivated by reciprocal altruism to...

A large literature following Hirsch (2005) has proposed citation-based indexes that could be used to rank academics. This paper examines how well several such indexes match labor market outcomes using data on the citation records of young tenured economists at 25 U.S. departments. Variants of...

This paper provides a critical review of models of the spread of the coronavirus (SARS-CoV-2) that have been influential in recent policy discussions. It notes potentially important features of the real- world environment that the standard models do not incorporate and discusses reasons why...

This paper explores differences in the frequency with which students from different schools reach high levels of math achievement. Data from the American Mathematics Competitions is used to produce counts of high-scoring students from more than two thousand public, coeducational, non-magnet,...

We study entry and bidding patterns in sealed bid and open auctions with heterogeneous bidders. Using data from U.S. Forest Service timber auctions, we document a set of systematic effects of auction format: sealed bid auctions attract more small bidders, shift the allocation towards these...

We analyze the extent to which efficient trade is possible in an ongoing relationship between impatient agents with hidden valuations (i.i.d. over time), restricting attention to equilibria that satisfy ex post incentive constraints in each period. With ex ante budget balance, efficient trade...

How much discretion should the monetary authority have in setting its policy? This question is analyzed in an economy with an agreed-upon social welfare function that depends on the randomly fluctuating state of the economy. The monetary authority has private information about that state. In the...

Using generalized random forests and rich Swedish administrative data, we show that the earnings effects of job displacement due to establishment closures are highly heterogeneous. We find as much heterogeneity within as across closing establishments, and within as across worker types defined by...

In this paper, we describe a computational implementation of the Synthetic difference-in-differences (SDID) estimator of Arkhangelsky et al. (2021) for Stata. Synthetic difference-in-differences can be used in a wide class of circumstances where treatment effects on some particular policy or...