Ricardo Lagos

A Unified Framework for Monetary Theory and Policy Analysis

Search‐theoretic models of monetary exchange are based on explicit descriptions of the frictions that make money essential. However, tractable versions of these models typically make strong assumptions that render them ill suited for monetary policy analysis. We propose a new framework, based on explicit micro foundations, within which macro policy can be studied. The framework is analytically tractable and easily quantifiable. We calibrate the model to standard observations and use it to measure the cost of inflation. We find that going from 10 percent to 0 percent inflation is worth between 3 and 5 percent of consumption—much higher than previous estimates.

Liquidity in Asset Markets with Search Frictions

We study how trading frictions in asset markets affect the distribution of asset holdings, asset prices, efficiency, and standard measures of liquidity. To this end, we analyze the equilibrium and optimal allocations of a search-theoretic model of financial intermediation similar to Duffie, Gârleanu and Pedersen (2005). In contrast with the existing literature, the model we develop imposes no restrictions on asset holdings, so traders can accommodate frictions by varying their trading needs through changes in their asset positions. We find that this is a critical aspect of investor behavior in illiquid markets. A reduction in trading frictions leads to an increase in the dispersion of asset holdings and trade volume. Transaction costs and intermediaries’ incentives to make markets are nonmonotonic in trade frictions. With the entry of dealers, these nonmonotonicities give rise to an externality in liquidity provision that can lead to multiple equilibria. Tight spreads are correlated with large volume and short trading delays across equilibria. From a normative standpoint we show that the asset allocation across investors and the number of dealers are socially inefficient.

Crime, Inequality, and Unemployment

There has been much discussion of the relationships between crime, inequality and unemployment. We construct a model where all three are endogenous. Introducing crime into otherwise standard models affects the labor market in several interesting ways. For example, we show how the crime rate affects the unemployment rate and vice-versa; how the possibility of criminal activity can lead to wage inequality among homogeneous workers; and how the possibility of crime can generate multiple equilibria in natural but previously unexplored ways. In particular, two fundamentally identical neighborhoods may easily end up with different levels of unemployment, inequality, and crime. The model can be used to study the equilibrium effects of anti-crime policies, such as changes in apprehension rates or jail sentences, as well as more traditional labor market policies such as unemployment insurance.

Money and capital as competing media of exchange

We construct a model in which capital competes with fiat money as a medium of exchange, and establish conditions on fundamentals under which fiat money can be both valued and socially beneficial. When the socially efficient stock of capital is too low to provide the liquidity agents need, they overaccumulate productive assets to use as media of exchange. When this is the case, there exists a monetary equilibrium that dominates the nonmonetary one in terms of welfare. Under the Friedman rule, fiat money provides just enough liquidity so that agents choose to accumulate the same capital stock a social planner would.

Crises and liquidity in over-the-counter markets

We study the efficiency of liquidity provision by dealers and the desirability of policy intervention in over-the-counter (OTC) markets during crises. We emphasizes two OTC frictions: finding counterparties takes time, and trade is bilateral and involves bargaining. We model a crisis as a shock that reduces investorsʼ asset demands, lasting until a random recovery time. In this context, dealers can provide liquidity to investors by accumulating asset inventories. When OTC frictions are severe, even well capitalized dealers may not find it privately optimal to accumulate inventories, and direct purchase by the government can improve welfare.

AN ON‐THE‐JOB SEARCH MODEL OF CRIME, INEQUALITY, AND UNEMPLOYMENT*

We extend simple search models of crime, unemployment, and inequality to incorporate on-the-job search. This is valuable because, although simple models are useful, on-the-job search models are more interesting theoretically and more relevant empirically. We characterize the wage distribution, unemployment rate, and crime rate theoretically, and use quantitative methods to illustrate key results. For example, we find that increasing the unemployment insurance replacement rate from 53 to 65 percent increases unemployment and crime rates from 10 and 2.7 percent to 14 and 5.2 percent. We show multiple equilibria arise for some fairly reasonable parameters; in one case, unemployment can be 6 or 23 percent, and crime 0 or 10 percent, depending on the equilibrium.

Dynamics, Cycles and Sunspot Equilibria in 'Genuinely Dynamic Fundamentally Disaggregative' Models of Money

This paper pursues a line of Cass and Shell, who advocate monetary models that are genuinely dynamic and fundamentally disaggregative and incorporate diversity among households and variety among commodities. Recent search-theoretic models fit this description. We show that, like overlapping generations models, search models generate interesting dynamic equilibria, including cycles, chaos, and sunspot equilibria. This helps us understand how alternative models are related, and lends support to the notion that endogenous dynamics and uncertainty matter, perhaps especially in monetary economies. We also suggest such equilibria in search models may be more empirically relevant than in some other models.

Money and Capital as Competing Media of Exchange

We construct a model in which capital competes with fiat money as a medium of exchange, and establish conditions on fundamentals under which fiat money can be both valued and socially beneficial. When the socially efficient stock of capital is too low to provide the liquidity agents need, they overaccumulate productive assets to use as media of exchange. When this is the case, there exists a monetary equilibrium that dominates the nonmonetary one in terms of welfare. Under the Friedman rule, fiat money provides just enough liquidity so that agents choose to accumulate the same capital stock a social planner would.

Crime, Inequality, and Unemployment, Second Version

There is much discussion of the relationships between crime, inequality, and unemployment. We construct a model where all three are endogenous. We find that introducing crime into otherwise standard models of labor markets has several interesting implications. For example, it can lead to wage inequality among homogeneous workers. Also, it can generate multiple equilibria in natural but previously unexplored ways; hence two identical neighborhoods can end up with different levels of crime, inequality, and unemployment. We discuss the effects of anti-crime policies like changing jail sentences, as well as more traditional labor market policies like changing unemployment insurance.

A Model of Job and Worker Flows

We develop an equilibrium search model that incorporates job‐to‐job transitions, exhibits instances of replacement hiring, and conceptually distinguishes between job and worker flows. We propose a notion of competitive equilibrium for random‐matching environments and study the extent to which it achieves an efficient allocation of resources. The model can be used to study how the permanent incomes and employment states of individual workers evolve over time, the amount of worker turnover in excess of job reallocation, the lengths of job tenures and unemployment durations, and the size and persistence of changes in workers’ incomes following displacements or job‐to‐job transitions.