Matthew Gibson

Ph.D. Candidate – Department of Economics


Research statement  (PDF)

Working Papers

Time use and productivity: the wage returns to sleep  (PDF)

with Jeffrey Shrader

While economists have long been interested in effects of health and human capital on productivity, less attention has been paid to the influence of time use. We investigate the productivity effects of the single largest use of time--sleep. Using a large set of time use diaries from the United States, we first demonstrate that later sunset time reduces worker sleep, creating plausibly exogenous variation. We then estimate the reduced-form effect of sunset time on wages. A short-run, sunset time one hour later decreases worker wages by 0.5%, while a one-hour later long-run average sunset time across locations decreases worker wages by 4.5%. After investigating this relationship and ruling out alternative hypotheses, we implement an instrumental variables specification that provides the first causal estimates of the impact of sleep on wages. In the short-run, a one-hour increase in mean weekly sleep increases worker wages by 1.5%. At the location level, a one-hour increase in long-run mean weekly sleep increases wage by 4.9%. Our results highlight the economic importance of sleep and pose potentially fruitful questions about the effects of time use on labor market outcomes.

Press: The Wall Street Journal  (PDF) | Huffington Post | Freakonomics Radio | Marketplace | The World Bank


Regulation-induced pollution substitution  (PDF)

Regulations may cause firms to re-optimize over pollution inputs, leading to unintended consequences. By regulating air emissions in particular counties, the Clean Air Act (CAA) gives firms incentives to substitute: 1) toward polluting other media, like landfills and waterways; and 2) toward pollution from plants in other counties. Using EPA Toxic Release Inventory data, I examine the effect of CAA regulation on these types of substitution. Regulated plants increase their ratio of water to air emissions by 44 percent. Regulation of an average plant increases air emissions at unregulated plants owned by the same firm by 17 percent, resulting in a net emissions increase.


The effects of road pricing on driver behavior and air pollution  (forthcoming, Journal of Urban Economics)  (PDF)

with Maria Carnovale

Exploiting the natural experiment created by an unanticipated court injunction, we evaluate driver responses to road pricing. We find evidence of intertemporal substitution toward unpriced times and spatial substitution toward unpriced roads. The effect on traffic varies with public transit availability. Net of these responses, Milan's pricing policy reduces air pollution substantially, generating large welfare gains. In addition, we use long-run policy changes to estimate price elasticities. Published version


Gray matters: air quality and human capital formation  (PDF)

with Prashant Bharadwaj, Joshua Graff Zivin, and Christopher Neilson

This paper examines the impact of fetal exposure to air pollution on 4th grade test scores in Santiago, Chile. We rely on comparisons across siblings which address concerns about locational sorting and all other time-invariant family characteristics that can lead to endogenous exposure to poor environmental quality. We also exploit data on air quality alerts to help address concerns related to short-run time-varying avoidance behavior, which has been shown to be important in a number of other contexts. We find a strong negative effect from fetal exposure to carbon monoxide (CO) on math and language skills measured in 4th grade. These effects are economically significant and our back of the envelope calculations suggest that the 50% reduction in CO in Santiago between 1990 and 2005 increased lifetime earnings by approximately 100 million USD per birth cohort.

Press: FiveThirtyEight  


The internet and local economic outcomes (coming soon)