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. Shopping Frictions with Household Heterogeneity: Theory & Empirics [article] [slides]

(The previous version of the article was distributed under the title ``Shopping Effort in Self-Insurance Economies.'')

This paper examines the impact of price dispersion on household consumption, highlighting the role of economic status in shaping purchasing behaviors. Leveraging detailed scanner data, I document high-earning employees pay 1.5 to 7% more than lower-earning ones for the same or similar goods. A causal link between income and the prices is established using the Economic Stimulus Act of 2008. The findings indicate that 8 to 22% of the increase in household spending following a transitory income shock is due to higher prices paid. Despite a broader variety in the consumption baskets of wealthier households, very few goods are tailored to specific income groups. Integrating consumer search with the savings problem, I propose a new model to reconcile the observed patterns and quantify the impact of retail-market frictions on consumption. Counterfactual analysis shows that over two-thirds of households face higher prices due to a price externality.

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

Applying a generalized random forest to Austrian administrative data, we uncover significant systematic heterogeneity in worker outcomes after job displacement. A quarter of workers face wage losses of 30%, while another quarter experience no losses or even gain. Among many factors, firm wage premia are the most important determinant of the wage loss heterogeneity, while workers' age is the most important for employment losses. Our findings suggest that earnings losses stem from mean reversion in firm wage premia rather than the destruction of firm-specific human capital. Compositional differences in individual characteristics account for most of the cyclicality in earnings losses.

Additional resources using the results from the paper:
  • General-audience presentation about using the GRF for estimation of heterogeneous treatment effects. [slides]
  • Presentation about using the GRF in business analytics. [slides]

3. The Consequences of the Covid-19 Job Losses:
Who Will Suffer Most and by How Much? (jointly with Andreas Gulyas) [article]

Using the universe of Austrian unemployment insurance records until May 2020, we document that the composition of UI claimants during the Covid-19 outbreak is substantially different compared to past times. Using a machine-learning algorithm from Gulyas and Pytka (2020), we identify individual earnings losses conditional on worker and job characteristics. Covid-19-related job terminations are associated with lower losses in earnings and wages compared to the Great Recession, but similar employment losses. We further derive an accurate but simple policy rule targeting individuals vulnerable to long-term wage losses.

Work in Progress

1. Looking into the Consumption Black Box: Evidence from Scanner Data (jointly with Daniel Runge)

Draft available upon request

Teaching

At Mannheim I give following lectures:

  1. Quantitative Macroeconomics with Heterogeneous Households [Ph.D. course]
  2. Julia tutorial prepared for my students can be found [here].
  3. Advanced Macroeconomics [M.Sc. course]
  4. Statistical Learning and Big Data with R [B.A. block seminar]
  5. Some prerecorded materials for students that introduce programming in R and statistical learning can be found [here].

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

Misc.

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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