Research Database

What quantitative lessons can we learn from models of endogenous technical change through innovative investments by firms for the impact of changes in the economic environment on the dynamics of aggregate productivity in the short, medium, and long run? We present a unifying model that nests a number of canonical models in the literature and characterize their positive implications for the transitional dynamics of aggregate productivity and their welfare implications in terms of two sufficient statistics. We review the current state of measurement of these two sufficient statistics and discuss the range of positive and normative quantitative implications of our model for a wide array of counterfactual experiments, including the link between a decline in the entry rate of new firms and a slowdown in the growth of aggregate productivity given that measurement. We conclude with a summary of the lessons learned from our analysis to help direct future research aimed at building models of endogenous productivity growth useful for quantitative analysis.

We examine the quantitative impact of policy-induced changes in innovative investment by firms on growth in aggregate productivity and output in a model that nests several of the canonical models in the literature. We isolate two statistics, the impact elasticity of aggregate productivity growth with respect to an increase in aggregate innovative investment and the degree of intertemporal knowledge spillovers in research, that play a key role in shaping the model’s predicted dynamic response of aggregate productivity, output, and welfare to a policy-induced change in the innovation intensity of the economy. Given estimates of these statistics, we find that there is only modest scope for increasing aggregate productivity and output over a 20-year horizon with uniform subsidies to firms’ investments in innovation of a reasonable magnitude, but the welfare gains from such a subsidy may be substantial.

Since the early 1990s, as the United States borrowed heavily from the rest of the world, employment in the U.S. goods-producing sector has fallen. We construct a dynamic general equilibrium model with several mechanisms that could generate declining goods-sector employment: foreign borrowing, nonhomothetic preferences, and differential productivity growth across sectors. We find that only 15.1 percent of the decline in goods-sector employment from 1992 to 2012 stems from U.S. trade deficits; most of the decline is due to differential productivity growth. As the United States repays its debt, its trade balance will reverse, but goods-sector employment will continue to fall.

The U.S. Great Recession featured a large decline in output and labor, tighter financial conditions, and a large increase in firm growth dispersion. We build a model in which increased volatility at the firm level generates a downturn and worsened credit conditions. The key idea is that hiring inputs is risky because financial frictions limit firms' ability to insure against shocks. An increase in volatility induces firms to reduce their inputs to reduce such risk. Out model can generate most of the decline in output and labor in the Great Recession and the observed increase in firms' interest rate spreads.

This paper argues that the comovement between inflation and economic activity is an important determinant of real interest rates over time and across countries. First, we show that for advanced economies, periods with more procyclical inflation are associated with lower real rates, but only when there is no risk of default on government debt. Second, we present a model of nominal sovereign debt with domestic risk-averse lenders. With procyclical inflation, nominal bonds pay out more in bad times, making them a good hedge against aggregate risk. In the absence of default risk, procyclical inflation yields lower real rates. However, procyclicality implies that the government needs to make larger (real) payments when the economy deteriorates, which could increase default risk and trigger an increase in real rates. The patterns of real rates predicted by the model are quantitatively consistent with those documented in the data.

Banks' ratio of the market value to book value of their equity was close to 1 until the 1990s, then more than doubled during the 1996-2007 period, and fell again to values close to 1 after the 2008 financial crisis. Sarin and Summers (2016) and Chousakos and Gorton (2017) argue that the drop in banks' market-to-book ratio since the crisis is due to a loss in bank franchise value or profitability. In this paper we argue that banks' market-to-book ratio is the sum of two components: franchise value and the value of government guarantees. We empirically decompose the ratio between these two components and find that a large portion of the variation in this ratio over time is due to changes in the value of government guarantees.

Businesses hold large quantities of cash reserves, which have average returns well below their investments in tangible capital. Businesses do this because these monetary assets provide services. One implication is that money services is a factor of production in capital theoretic valuation equilibrium models. Our aggregate production function is consistent with both the classical demand for money function relationship and with extended periods of near zero short-term nominal interest rates. In our model economy, there is a 100 percent reserve requirement on all demand deposits. Demand deposits are legal tender. We find (i) money services in the production function necessitates revisions in the national accounts; (ii) monetary and fiscal policy cannot be completely separated; (iii) for a given policy, equilibrium is either unique or does not exist; and (iv) Friedman’s monetary satiation is not optimal. We make quantitative comparisons between interest rate targeting regimes and between inflation rate targeting regimes. The best inflation rate target was 2 percent.

Brazil has had a long period of high inflation. It peaked around 100 percent per year in 1964, decreased until the first oil shock (1973), but accelerated again afterward, reaching levels above 100 percent on average between 1980 and 1994. This last period coincided with severe balance of payments problems and economic stagnation that followed the external debt crisis in the early 1980s. We show that the high-inflation period (1960-1994) was characterized by a combination of fiscal deficits, passive monetary policy, and constraints on debt financing. The transition to the low-inflation period (1995-2016) was characterized by improvements in all of these features, but it did not lead to significant improvements in economic growth. In addition, we document a strong positive correlation between inflation rates and seigniorage revenues, although inflation rates are relatively high for modest levels of seigniorage revenues. Finally, we discuss the role of the weak institutional framework surrounding the fiscal and monetary authorities and the role of monetary passiveness and inflation indexation in accounting for the unique features of inflation dynamics in Brazil.

We study the urban structure of the City of Detroit. Following many decades of decline, the city’s current urban structure is clearly not optimal for its size, with a business district immediately surrounded by a ring of largely vacant neighborhoods. We propose a model with residential externalities that features multiple equilibria at the neighborhood level. In particular, developing a residential area requires the coordination of developers and residents, without which it may remain vacant even if its fundamentals are sound. We embed this mechanism in a quantitative spatial economics model and use it to rationalize current city allocations. We then use the model to evaluate existing strategic visions to revitalize Detroit, and to design alternative plans that rely on ‘development guarantees’ to yield better outcomes. The widespread effects of these policies underscore the importance of using a general equilibrium framework to evaluate policy proposals.