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Essays in Modern Macroeconomics



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Wales, Daniel 


This PhD thesis consists of a short introduction followed by three papers. Each paper examines a different topic within the broad area of modern monetary and international macroeconomics.

The first paper, Product Quality, Measured Inflation and Monetary Policy, written in collaboration with Alex Rodnyansky and Alejandro van der Ghote, fills a gap in the New Keynesian literature, which has largely ignored product quality adjustments. This paper proposes a tractable model of a New Keynesian (NK) economy where, in addition to the standard price and quantity channels, firms are able to endogenously adjust the quality of their products in response to shocks. This new model, featuring endogenous product quality changes subject to adjustment costs, nests the canonical New Keynesian model, which is frequently used as the starting point for policy analysis by central banks. In this framework, endogenous product quality choices imply a larger slope than the traditional NK Phillips curve as, for a positive productivity shock that lowers marginal costs, quality-adjusted prices decline because firms are simultaneously able to increase the quality of their products. Allowing firms to adjust product quality also amplifies the economy’s response to productivity shocks. Following a positive productivity shock the natural real interest rate decreases by more as households look to smooth a larger increase in consumption, which is boosted by a rise in both the quantity and quality of the goods they consume. As a result, monetary policy responds by altering the nominal interest rate by more for a given productivity shock. Model misspecification of imperfectly observable quality adjustments matters more for macroeconomic stabilization than the mismeasurement of those adjustments. With no misperception of product quality by the monetary authority, the principles for optimal monetary policy are, nonetheless, unchanged as the product quality extensions to the canonical NK model preserve divine coincidence.

My second PhD paper, The Impact of Large-Scale Asset Purchases on Wealth Inequality examines the relationship between monetary policy and household wealth inequality through changes in the size and composition of the central bank’s balance sheet. I focus on the impact on household wealth inequality through the financial portfolio rebalancing channel of monetary policy transmission. I construct a theoretical model that has multiple assets (of differing liquidity), banks and heterogeneous agents, who experience idiosyncratic labor productivity shocks. This model is carefully calibrated to reproduce theoretical levels of wealth inequality which match those observed in the US Survey of Consumer Finances. I use the model to replicate the changes in the Federal Reserve’s balance sheet which arose in the aftermath of the 2007/2008 financial crisis. This shows that an expansion of the central bank’s balance sheet can materially alter the distribution of wealth, causing inequality to increase, while even extreme changes in the composition of the central bank’s balance sheet (for example through maturity extension) have little effect. This arises as central bank purchases of longer term assets cause households to hold additional liquid financial wealth. Liquid financial assets are unevenly distributed in the population, and hence wealth inequality measures increase. When the model is calibrated to match the Federal Reserve’s Large Scale Asset Purchases (LSAPs) from 2008 until 2014, wealth inequality increases by 3.8%, as measured by the Gini coefficient, suggesting this channel leads to a significant increase in wealth inequality.

The final PhD paper, The Rise of Harrod-Balassa-Samuelson, begins by documenting two stylised facts. Firstly, over the past 70 years the positive cross-country relationship between aggregate consumer prices and real output per capita has strengthened (i.e. a rise in the Harrod-Balassa-Samuelson effect), as demonstrated using data from the Penn World Tables. Secondly, border frictions have increased over the same time frame, with international borders effectively becoming wider and an increasing failure of the Law of One Price (LOOP). I construct my own dataset of city-level relative prices using national sources across five continents to document the increasing failure of the LOOP. I then use a two-country endowment model with a domestic distribution services sector to construct an equilibrium failure of the LOOP. An increase in the relative size of the distribution services sector can simultaneously explain both stylized facts, while the standard explanation (a higher share of non-traded goods) may only explain the first. Furthermore, I extend the model to include production by monopolistically competitive firms, before solving and calibrating the model to closely replicate the two stylised facts.





Geraats, Petra


economics, exchange rates, international economics, macroeconomics, monetary economics, monetary policy, wealth inequality


Doctor of Philosophy (PhD)

Awarding Institution

University of Cambridge