PUBLICATONS
The Skill Complementarity of Broadband Internet with A. Akerman and M. Mogstad, Quarterly Journal of Economics, 130(4), 2015 [online appendix]
Does adoption of broadband internet in firms enhance labor productivity and increase wages? Is this technological change skill biased or factor neutral? We combine several Norwegian data sets to answer these questions. A public program with limited funding rolled out broadband access points and provides plausibly exogenous variation in the availability and adoption of broadband internet in firms. Our results suggest that broadband internet improves (worsens) the labor market outcomes and productivity of skilled (unskilled) workers. We explore several possible explanations for the skill complementarity of broadband internet. We find suggestive evidence that broadband adoption in firms complements skilled workers in executing nonroutine abstract tasks, and substitutes for unskilled workers in performing routine tasks. Taken together, our findings have important implications for the ongoing policy debate over government investment in broadband infrastructure to encourage productivity and wage growth.
Incidence and Distributional Effects of Value Added Taxes, The Economic Journal, 129(618) 2019 [online appendix]
This article examines the incidence and distributional effects of value added taxes (VAT). A sharp change in the VAT policy on food in Norway is exploited. My findings suggest that taxes levied on food are completely shifted to consumer prices, while there is little spill-over effects to most other goods. To understand the distributional effects of the reform, one uses expenditure data and estimate the compensating variation of the tax induces price changes. I find that lowering the VAT on food attenuates inequality in consumer welfare, in part because households adjust their spending patterns in response to the price change.
WORKING PAPERS
Green Waste with M. Grindaker, T. G. Meling, and M. Mogstad, 2026 , revision requested at the Journal of Political Economy
We test for and measure green waste: the misallocation of public subsidies for green investment projects. Our context is a major Norwegian program for green investment subsidies. We develop a model of subsidy allocation and apply it to detailed project-level data on carbon emissions and subsidy amounts for both marginal and inframarginal projects. We find that decision-makers could have achieved the same level of emission reductions at less than half the cost. To isolate the sources of this green waste, we use data on both ex-ante expected and ex-post realized emission reductions for each project. We find that decision-makers are able ex-ante to identify the projects with the highest ex-post emission reductions but unwilling to select them.
Chasing an Elusive Target: Measuring Productivity Growth under Factor-Biased Technical Change with A. Akerman, 2025 [online appendix] , Revision requested by the Scandinavian Journal of Economics
We show that standard growth-accounting methods understate productivity growth when technological change is factor-biased. We document this bias in two settings. First, using the NBER–CES Productivity Database for U.S. manufacturing (1958–2011), we find that conventional estimates underreport TFP growth by 10 percent, with the gap nearly doubling after 2000. Second, exploiting the staggered rollout of broadband internet in Norway, we show that treating the technology as Hicks-neutral obscures substantial productivity gains, while accounting for factor bias reveals that broadband adoption raised firm-level TFP by about 3.5 percent. Across both applications, the common assumption of time-invariant, Hicks-neutral production functions leads to systematically downward-biased estimates of productivity growth.
The Welfare Effects of Marginal and Nonmarginal Changes in the Sales Taxes in the U.S., with L. H. de Frahan, 2026 (submitted)
We study the welfare effects of both marginal and larger non-marginal changes in sales taxes. The analysis uses a panel of sales taxes in the U.S. at the county and state level. This data allows us to estimate the effect on prices and quantities of the observed changes in sales tax rates. We propose and apply a framework that uses such effect estimates to bound the welfare effects of actual and counterfactual sales tax reforms. The bounds are informative even under imperfect competition or with nonlinear demand and supply curves. We find that the marginal value of public funds is close to one, even for large counterfactual changes in sales tax. We also construct informative bounds on how the welfare effects vary across states depending on initial prices and tax rates. These bounds are policy relevant as sales taxes are set by local governments and vary across areas.
Supply and Demand with Market Heterogeneity, with L. H. de Frahan, M. Mogstad, A. Torgovitsky and O. Volpe, 2026 (submitted)
We revisit the classic identification problem of separating supply and demand for a homogeneous good using data from multiple markets. We allow markets to be heterogeneous according to unobservables, a feature that arises if there are unobservable differences in consumer preferences or firm technology. We develop a new identification analysis based on hypothetical market types. We use this analysis to show how nonparametric, economically motivated assumptions carry empirical restrictions for a wide range of target parameters, including elasticities, but also welfare parameters, such as consumer surplus. Then, we develop computationally tractable methods for implementing partially identified linear random coefficients models in which the slopes of supply and demand are heterogeneous. We apply these methods to estimate the welfare impact and incidence of sales taxes in the United States
WORK IN PROGRESS
The Distributional Incidence of Sales Taxes in the U.S., with L. H. de Frahan
Globalization and the role of labor market institutions, with O. L. Vestad