Cześć!

I'm a Postdoctoral Researcher at the University of Mannheim, where in the next academic term I will become an Assistant Professor (Juniorprofessor). I specialize in Macroeconomics, in particular in 1. consumption; and 2. search theory. My technical interests also cover computational economics and (applied) statistical learning. For some time, I've focused on incorporating frictions in the purchasing technology into the standard incomplete markets model.

Research

Working Papers

1. Shopping Effort in Self-Insurance Economies - Job Market Paper [article] [slides]

How are income fluctuations transmitted to consumption decisions if the law of one price does not hold? I propose a novel and tractable framework to study search for consumption as part of the optimal savings problem. Due to frictions in the retail market, households have to exert some effort to purchase the consumption good. This effort has two components: 1. effort to search for price bargains; 2. effort required to purchase consumption of a given size. These two motives are necessary to replicate two seemingly contradictory shopping patterns observed in the data, namely: higher time spent shopping by the unemployed and retirees and (conditioned on being employed) the positive elasticity of shopping time with respect to labor income. The former is well known in the literature, while the latter is new and I document it using data from the American Time Use Survey. The model allows me to reconcile the traditional savings theory with households' shopping behavior in a quantitatively meaningful way. As I show frictions in the purchasing technology generate important macroeconomic implications for modeling inequality and, in general, household consumption.

2. Bargain Hunting in Equilibrium Price Dispersion

In this article, I study equilibrium properties of a standard model of endogenous price distribution due to Burdett and Judd (1983). In search economies of this type in most cases there are two dispersed equilibria, low-search and high-search one. I show that the low-search equilibrium is unstable while the high-search equilibrium is stable. What is important every allocation can be characterized only as one of those types. This finding substantially narrows the range of allocations, in which the price dispersion is stable and its form is not a temporary phenomenon. To recover the stability of every allocation I propose a refinement of the original model, which gives rise to one unique symmetric dispersed equilibrium. This equilibrium is shown to be stable and it can be used to rationalize every allocation. In addition to this, in contrast to the original model the degenerate Diamond (1971)-type equilibrium is unstable.

Work in progress

1. General Equilibrium Theory of Shopping, Consumption, and Price Dispersion (jointly with Greg Kaplan)

2. Labor Market and Business Cycle: Expansion vs. Contraction

3. Shape-Preserving Chebyshev Approximation of Multivariate Functions

References

People who can say something more about my research agenda (and me):

1. Árpád Ábrahám (EUI);
2. Piero Gottardi  (EUI);
3. Greg Kaplan (UChicago);
4. Mark Aguiar (Princeton).

Résumé

You can find my CV here.

Teaching

In the course of my Master and PhD studies I was a TA for some courses:

1. Macroeconomics [PhD course @EUI];
2. Advanced Statistical Learning in R/S-Plus [MA course @SGH];
3. Introduction to Econometrics [BA course @SGH];
4. Operations Research [BA course @SGH].

Here you can find the (old) website with teaching materials.

Contact

Department of Economics
Universität Mannheim
L7 3-5, Office 2.09
68161 Mannheim, Germany
Phone: +49.621.181.181.7
e-mail: p***@uni-mannheim.de

Misc.

In my free time I (used to) write for Hummus Œconomicus, a Polish popular-science blog about economics. Here you can find my posts (sadly only in Polish).

If you're curious about the pronounciation of my given name it goes by [kʂɨʂt̪ɔf] in IPA. But Christoph is totally fine with me.

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