Krzysztof Pytka

Cześć!

I'm an Assistant Professor (Juniorprofessor) of Quantitative Macroeconomics at the University of Mannheim. Image of Krzysztof Pytka In my research I am interested how the heterogeneity of individuals affects macroeconomic outcomes. Tools that I use span structural models and machine learning.

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

Résumé

You can find my CV here.

Research

Working Papers

1. Understanding the Sources of Earnings Losses After Job Displacement:
A Machine-Learning Approach (jointly with Andreas Gulyas) [article] [slides]

We document the sources behind earnings losses after job displacement adapting the generalized random forest due to Athey et al. (2019). Using administrative data from Austria over three decades, we show that displaced workers face large and persistent earnings losses. We identify substantial heterogeneity in losses across workers. A quarter of workers face cumulative 11-year losses higher than 2 times their pre-displacement annual income, while another quarter experiences losses less than 1.1 times their income. The most vulnerable are older high-income workers employed at well-paying firms in the manufacturing sector. Our methodology allows us to consider many competing theories of earnings losses prominently discussed in the literature. The two most important factors are the displacement firm's wage premia and the availability of well paying jobs in the local labor market. Our overall findings provide evidence that earnings losses can be understood by mean reversion in firm rents and losses in match quality, rather than by a destruction of firm-specific human capital.

Additional resources using the results from the paper:
  • Web app predicting earnings losses conditioned on individual characteristics
  • General-audience presentation about using the GRF for estimation of heterogeneous treatment effects. [slides]
  • Presentation about using the GRF in business analytics. [slides]

2. Shopping Effort in Self-Insurance Economies (in revision) [article] [slides]

Best Paper Prize for Young Economists at the WIEM’16 conference.

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.

3. 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

Teaching

At Mannheim I give following lectures:

  1. Quantitative Macroeconomics with Heterogeneous Households [Ph.D. course];
  2. Advanced Macroeconomics [M.Sc. course];
  3. Statistical Learning and Big Data with R [B.A. course].

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

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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