Annual Review of Economics - Volume 13, 2021

Infectious diseases, ideas, new products, and other infectants spread in epidemic fashion through social contact. The COVID-19 pandemic, the proliferation of fake news, and the rise of antimicrobial resistance have thrust economic epidemiology into the forefront of public policy debate and reinvigorated the field. Focusing for concreteness on disease-causing pathogens, this review provides a taxonomy of economic-epidemic models, emphasizing both the biology/immunology of the disease and the economics of the social context. An economic epidemic is one whose diffusion through the agent population is generated by agents’ endogenous behavior. I highlight properties of the equilibrium epidemic trajectory and discuss ways in which public health authorities can change the game for the better by (a) imposing restrictions on agent activity to reduce the harm done during a viral outbreak and (b) enabling diagnostic-informed interventions to slow or even reverse the rise of antibiotic resistance.

It is increasingly evident that the direction of technological change responds to economic incentives. We review the literature on directed technical change in the context of environmental economics and labor economics, and we show that these fields have much in common both theoretically and empirically. We emphasize the importance of a balanced growth path and show that the lack of such a path is closely related to the slow development of green technologies in environmental economics and to growing inequality in labor economics. We discuss whether the direction of innovation is efficient.

Does inflation vary across the income distribution? This article reviews the growing literature on inflation inequality, describing recent advances and opportunities for further research in four areas. First, new price index theory facilitates the study of inflation inequality. Second, new data show that inflation rates decline with household income in the United States. Accurate measurement requires granular price and expenditure data because of aggregation bias. Third, new evidence quantifies the impacts of innovation and trade on inflation inequality. Contrary to common wisdom, empirical estimates show that the direction of innovation is a significant driver of inflation inequality in the United States, whereas trade has similar price effects across the income distribution. Fourth, inflation inequality and non-homotheticities have important policy implications. They transform cost-benefit analysis, optimal taxation, the effectiveness of stabilization policies, and our understanding of secular macroeconomic trends—including structural change, the decline in the labor share and interest rates, and labor market polarization.

This article describes the emerging game-theoretic framework for modeling long-term contractual relationships with moral hazard. The framework combines self-enforcement and external enforcement, accommodating alternative assumptions regarding how actively the parties initially set and renegotiate the terms of their contract. A progression of theoretical components is reviewed, building from the recursive formulation of equilibrium continuation values in repeated games. A principal-agent setting serves as a running example.