Timo Boppart

Institute for International Economic Studies
Stockholm University
SE-106 91 Stockholm
Tel: +46 (0)8 16 35 52


NBER Working Papers and Publications

December 2017Exploiting MIT Shocks in Heterogeneous-Agent Economies: The Impulse Response as a Numerical Derivative
with Per Krusell, Kurt Mitman: w24138
We propose a new method for computing equilibria in heterogeneous-agent models with aggregate uncertainty. The idea relies on an assumption that linearization offers a good approximation; we share this assumption with existing linearization methods. However, unlike those methods, the approach here does not rely on direct derivation of first-order Taylor terms. It also does not use recursive methods, whereby aggregates and prices would be expressed as linear functions of the state, usually a very high-dimensional object (such as the wealth distribution). Rather, we rely merely on solving nonlinearly for a deterministic transition path: we study the equilibrium response to a single, small "MIT shock'' carefully. We then regard this impulse response path as a numerical derivative in sequence ...
November 2017Missing Growth from Creative Destruction
with Philippe Aghion, Antonin Bergeaud, Peter J. Klenow, Huiyu Li: w24023
Statistical agencies typically impute inflation for disappearing products based on surviving products, which may result in overstated inflation and understated growth. Using U.S. Census data, we apply two ways of assessing the magnitude of "missing growth" for private nonfarm businesses from 1983-2013. The first approach exploits information on the market share of surviving plants. The second approach applies indirect inference to firm-level data. We find: (i) missing growth from imputation is substantial – at least 0.6 percentage points per year; and (ii) most of the missing growth is due to creative destruction (as opposed to new varieties).
May 2016Labor Supply in the Past, Present, and Future: a Balanced-Growth Perspective
with Per Krusell: w22215
What explains how much people work? Going back in time, a main fact to address is the steady reduction in hours worked. The long-run data, for the U.S. as well as for other countries, show a striking pattern whereby hours worked fall steadily by a little below a half of a percent per year, accumulating to about a halving of labor supply over 150 years. In this paper, we argue that a stable utility function defined over consumption and leisure can account for this fact, jointly with the movements in the other macroeconomic aggregates, thus allowing us to view falling hours as part of a macroeconomy displaying balanced growth. The key feature of the utility function is an income effect (of higher wages) that slightly outweighs the substitution effect on hours. We also show that our proposed ...
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