The Macroeconomic Implications of Learning by Shopping
- Autores: Ángelo Gutiérrez Daza
- Directores de la Tesis: Jordi Galí Garreta (dir. tes.), Davide Debortoli (codir. tes.)
- Lectura: En la Universitat Pompeu Fabra ( España ) en 2022
- Idioma: español
- Tribunal Calificador de la Tesis: Luigi Paciello (presid.), Albert Marcet Torrens (secret.), Mirko Wiederholt (voc.)
- Programa de doctorado: Programa de Doctorado en Economía, Finanzas y Empresa por la Universidad Pompeu Fabra
- Materias:
- Enlaces
- Tesis en acceso abierto en: TDX
- Resumen
- español
La evidencia empírica sugiere que los consumidores forman percepciones sobre la inflación a partir de los precios observados durante sus compras personales. Esta tesis investiga las consecuencias de esta fricción de información para la transmisión de los choques macroeconómicos y el diseño de la política monetaria. El primer capítulo introduce esta fricción de información en un modelo Neo-Keynesiano y encuentra que la fricción propaga los choques de demanda y hace que la pendiente de la curva de Phillips dependa de la política monetaria. El segundo capítulo estudia cómo puede un banco central estabilizar la economía de este modelo siguiendo una regla de política simple, y encuentra que una versión más estricta del principio de Taylor es necesaria para poder lograr este objetivo. Finalmente, el tercer capítulo muestra que una extensión del modelo permite que los márgenes de precio de las firmas respondan de forma procíclica a los choques de demanda.
- English
Inflation plays a central role in macroeconomic theory and policy. Academics, central bankers, and market participants continuously pay attention to inflation indicators like the Consumer Price Index (CPI). Given the resources devoted to controlling and forecasting inflation, one would expect consumers would also be highly attentive to inflation developments.
But the empirical evidence suggests that most consumers do not pay attention to official inflation statistics: Their perception of current inflation differs substantially from the inflation reflected in the CPI. Moreover, providing consumers with information about inflation statistics has only partial and short-lived effects on their expectations. Instead of using public signals, the empirical evidence suggests that consumers rely on their own shopping experiences to form beliefs about inflation. In other words, they "learn by shopping".
This dissertation studies the macroeconomic consequences of "learning by shopping" (henceforth LBS). It contains three chapters that study how this information friction affects the transmission of macroeconomic shocks, the design of monetary policy, and the cyclical response of price-markups.
Chapter 1 presents the theoretical framework at the core of this dissertation. This chapter introduces LBS in a standard New Keynesian model as an information friction on the households’ block of a standard New Keynesian model: I assume households acquire idiosyncratic noisy signals about inflation from the prices they observe while shopping for the different goods in their consumption basket. Using this information, they form beliefs about current and future inflation and make decisions conditional on those beliefs. I use the model to study analytically and quantitatively how this information friction affects the transmission of aggregate shocks and the design of monetary policy. Three results from this analysis stand out.
First, LBS propagates the impact of demand shocks on output. The information friction affects households’ perception of the real wage, altering their labor supply decision and allowing nominal shocks to have real effects. It also distorts households’ perception of their permanent income, amplifying the impact of demand shocks on consumption, employment, and output.
Second, the interaction of this information friction with nominal rigidities in prices amplifies the impact of demand shocks on output. Moreover, the propagation of demand shocks when both frictions are present can be larger than the sum of the effect of each friction considered in isolation.
Finally, LBS makes the slope of the Phillips curve depend on the degree of anchoring of households’ beliefs about inflation. But the degree of anchoring itself is a function of the strength with which the central bank responds to deviations of the inflation rate from its target. For this reason, a more hawkish monetary policy can simultaneously anchor households’ inflation expectations, flatten the Phillips curve, and lower the volatility and persistence of inflation. Perhaps surprisingly, the model suggests that such a policy also makes output and employment more responsive to exogenous shifts in aggregate demand.
Chapter 2 builds on the model presented in the previous chapter to study the ability of the central bank to stabilize the economy by targeting inflation. The LBS assumption implies that households do not directly observe monetary policy shocks or the interest rate but can learn about their effects from the market signals acquired during their shopping experiences. For this reason, the model serves as a laboratory to study the effects of monetary policy in an economy where consumers don’t pay attention (at least directly) to the macroeconomy.
The main result of this analysis is that the Taylor principle is no longer sufficient to guarantee the uniqueness of the equilibrium. Inattention dampens the effect of movements in the central bank’s interest rate on the perceived real rate by households. However, the central bank can offset this dampening, regardless of the degree of inattention, by following a modified version of this principle requiring a stronger interest rate response to inflation. This principle guarantees that the central bank can eventually communicate the effect of its policies to households through the market signals, they observe every period.
Chapter 3 studies the cyclical properties of markups when consumers learn by shopping. Empirical evidence suggests that demand shocks produce both an expansion in economic activity and an increase in price markups. This chapter shows that the model introduced can account for both observations when consumers also use their shopping experiences to learn about relative prices. The reason is that this friction introduces a dynamic trade-off on firms’ pricing decisions, making aggregate markups respond to demand shocks. A calibrated version of the model produces a persistent and hump-shaped increase in output after a demand shock. This response is accompanied by a small increase in price markups; despite the absence of any other real or nominal rigidity in the model.
- español
