We use firm-level data to document that private businesses experience large fluctuations in their profit shares. These are due to large, fat-tailed, and transitory changes in output that are not fully accompanied by changes in their inputs. We interpret this evidence using a model of entrepreneurial dynamics. Because firms can limit their exposure to risk by operating at a smaller scale, our model predicts large macroeconomic losses from uninsurable business risk, much larger than those stemming from credit constraints. While self-financing allows entrepreneurs to quickly overcome credit constraints, even wealthy entrepreneurs remain considerably exposed to risk. (JEL D33, E02, E44, G32, L25, L26)
Moretti (2021) reports a positive elasticity between technology cluster size and patenting, and uses an event study and instrumental variables regressions to justify a causal interpretation. The event study does not use the variation generated by inventors moving across cities, and the instrument is constructed incorrectly due to a coding error. I run a corrected event study and fix the coding error, and find null effects. The reported elasticity may not be causal. (JEL J24, L60, O31, O34, R32)
What is the optimal response of a resource exporter when a price cap is imposed on its main export? This paper develops a dynamic framework incorporating stochastic prices, financial frictions, and market power to study this novel tool of statecraft. With the right design, a price cap can incentivize increased extraction, stabilizing prices in the global market. But the stabilizing effects diminish when there is leakage outside the cap. Consequently, weak enforcement of the policy worsens the trade-off faced by the sanctioning policymaker. We provide a systematic approach to setting and enforcing an optimal cap level in these circumstances. (JEL F12, F14, F51, L71, P28, P33, Q35)
We show that, depending on how the impact of omitted variables is measured, it can be substantially easier for omitted variables to flip coefficient signs than to drive them to zero. This behavior occurs with “Oster's delta” (Oster 2019a), a widely reported robustness measure. Consequently, any time this measure is large—suggesting omitted variables may be unimportant—a much smaller value reverses the sign of the parameter of interest. We propose a modified measure of robustness to address this concern. We illustrate our results in four empirical applications and two meta-analyses. We implement our methods in the companion Stata module “regsensitivity.” (JEL C18, C21, C52)
I study how firm market power and worker bargaining power shape wages and welfare. Using French micro-data, I document patterns linking wages and firm market power that existing models cannot explain. A model in which firms produce vertically differentiated goods and share profits with workers explains those patterns. The model (i) reveals new challenges in estimating monopsony and bargaining power, proposing an alternative approach; (ii) shows that the passthrough of firm-specific shocks to wages depends on the type of shock; (iii) explains how markups shape firm wage premia; and (iv) formalizes how strengthening worker bargaining power affects wages and welfare. (JEL D22, J31, J42, J52, L12, L22)
Preschool-aged children get sick frequently and spread disease to other family members. Despite the universality of this experience, there is limited causal evidence on the magnitudes and consequences of these externalities, especially for infant siblings with developing immune systems and brains. We show in Danish administrative data that during infancy, younger siblings have two to three times higher hospitalization rates for respiratory conditions than older siblings. We combine birth order and within-municipality variation in respiratory disease prevalence among young children, finding lasting differential impacts of early-life respiratory disease exposure on younger siblings' earnings, educational attainment, chronic respiratory health, and mental health-related outcomes. (JEL D13, D62, I12, J12, J13, J24, J31)
We propose a novel identification strategy to isolate exogenous immigration shocks across US counties, by interacting quasi-random variations in the composition of ancestry across counties with the contemporaneous inflow of migrants from different countries. We show a positive causal impact of immigration on local innovation and wages at the five-year horizon. The positive dynamic impact of immigration on innovation and wages dominates the short-run negative impact of increased labor supply. A structural estimation of a model of endogenous growth and migrations suggests the increased immigration to the United States since 1965 may have increased innovation and wages by 5 percent. (JEL J15, J22, J31, J61, O31, R11, R23)
Item-level transactions data yield cost-of-living indices that can account for quality change and consumer substitution. Transactions data require confronting the rapid turnover of items because prices of new and existing products are interrelated in equilibrium. This paper evaluates multiple approaches to measuring quality change at scale. It shows that a hedonic superlative approach—using econometrics or machine learning for hedonic estimation combined with index formulas that require simultaneous observation of item-level price and expenditure—yields improved measures of the cost of living. Accounting for ubiquitous quality change and for consumer substitution yields lower measures of inflation than traditional, official methods. (JEL C43, C45, E31, L15, L81)
We examine how social interactions and friendships shape students’ political opinions in a natural experiment at Sciences Po, a leading French university specializing in social and political sciences. The quasi-random assignment of students into short-term integration groups before their academic curriculum reduces political opinion gaps and fosters friendship formation. Using same-group membership as an instrumental variable for friendship, we find that friendship reduces opinion differences by 44 percent of the mean opinion gap. Our evidence supports a homophily-enforced mechanism: Friendships form among initially politically similar students, leading them to join political associations together, reinforcing their similarity. (JEL C93, D72, Z13)
Conflict along transportation routes during Somalia’s al-Shabaab insurgency significantly increases maize prices at distant locations, decreasing food security, health, and education. Estimated conflict risk has strong price effects independently of realized conflict, highlighting the importance of safety concerns. A model of least-cost route choice in the presence of conflict reveals that more and shorter alternative routes to circumvent conflict can lower prices but their effectiveness diminishes as violence becomes more correlated across routes. Alternatively, securing key transportation routes would alleviate price increases. A market access approach suggests spatial spillovers of conflict also matter for prices of more general baskets of food and nonfood items. (JEL D74, I15, I25, O15, O17, Q11, R41)
The influence of on-the-job training and supervisors, especially in high-stakes settings like policing, is poorly understood. Examining a central behavior in the debate surrounding police reform, we investigate the impact of a field training officer (FTO) on a recruit's use of force. Leveraging a setting with conditional as-good-as-random assignment, we demonstrate a causal link between FTO and recruit use of force. A 1 standard deviation increase in FTO force propensity leads to a 14 to 18 percent rise in recruit force, persisting for at least two years. This underscores field training's impact and reveals a promising avenue for reform. (JEL D91, J24, J45, K42, M53)
This paper shows that the wage assimilation of immigrants is the result of the intricate interplay between individual skill accumulation and dynamic labor market equilibrium effects. When immigrants and natives are imperfect substitutes, rising immigrant inflows widen the wage gap between them. Using a production function framework in which workers supply both general and host-country-speciic skills, we show that this labor market competition channel explains about one-ifth of the large increase in the average immigrant-native wage gap across arrival cohorts in the United States since the 1960s. The results further reveal substantial heterogeneity across different groups of immigrants. (JEL J22, J23, J24, J31, J61, K37, O33)
A common interpretation of Pareto-efficient policies is that, for some cardinal utility representations of preferences, they maximize utilitarian welfare. We show in the context of income taxation that such cardinalizations are often extreme, requiring unbounded curvature of utility with respect to consumption. Taxes can be justified as utilitarian without these extreme cardinalizations if and only if revenues are decreasing and concave in a class of narrowly targeted tax cuts. We reformulate this condition as a sufficient-statistics test. The test fails whenever elasticities of taxable income are too heterogeneous within some income level, as we argue is empirically likely.
We study social preferences in settings where someone who chooses on behalf of others knows how those individuals rank the available options but may lack cardinal information concerning those comparisons. Contrary to majoritarian principles, most people place more weight on preventing least preferred outcomes for others than on enabling most preferred outcomes. Ranks matter both intrinsically and because they provide a basis for inferring cardinal utility. Ordinal aggregation principles are stable across domains and countries with divergent political traditions. Designing attractive social choice mechanisms is challenging in practice partly because aggregation principles that make manipulation difficult yield outcomes people consider normatively unappealing. (JEL C91, D71, D72)
We use Danish administrative data to examine the effects of parental death on labor market outcomes. Leveraging the timing of sudden, first parental deaths and a matched-control difference-in-differences strategy, we find that men's earnings decline by 2 percent, while women's earnings decline by 3 percent following a parental death. Both women and men experience mental health deterioration, leading to increased use of psychological assistance and prescriptions for mental health conditions and opioids. Women with young children experience a comparatively larger earnings decline (around 4 percent) likely due to the loss of informal childcare. (JEL D91, I12, J13, J16, J31)
