Working Papers
The Labor Market Effects of Restricting Refugees’ Employment Opportunities
With Andreas Beerli, Selina Kurer, Dominik Hangartner, Michael Siegenthaler (American Economic Review, R&R)
Abstract: This paper investigates whether employment restrictions contribute to refugees having poorer labor market outcomes than citizens. Utilizing linked register data from Switzerland and within-canton policy variation between 1999-2015, we find substantial negative effects on employment and earnings when refugees are barred from working upon arrival, restricted from specific sectors or regions, or face resident prioritization. Removing 10% of refugees' outside options reduces job-to-job mobility by 7.5% and wages by 3.0%, widening the wage gap to citizens in similar jobs. The restrictions depress refugees' labor market outcomes even after they apply, but do not spur emigration nor benefit other immigrants.
An Introduction to Double/Debiased Machine Learning
With Victor Chernozhukov, Christian Hansen, Damian Kozbur, Mark Schaffer, Thomas Wiemann (Journal of Economic Literature, R&R)
Abstract: This paper provides a practical introduction to Double/Debiased Machine Learning (DML). DML provides a general approach to performing inference about a target parameter in the presence of nuisance parameters. The aim of DML is to reduce the impact of nuisance parameter estimation on estimators of the parameter of interest. We describe DML and its two essential components: Neyman orthogonality and cross-fitting. We highlight that DML reduces functional form dependence and accommodates the use of complex data types, such as text data. We illustrate its application through three empirical examples that demonstrate DML's applicability in cross-sectional and panel settings.
Welfare Benefits and Refugee Crime
With Daniel Auer, Michaela Slotwinski, Dominik Hangartner, Selina Kurer, Stefanie Kurt, Alois Stutzer
Abstract: Despite intense policy debates, the relationship between social welfare and refugee crime remains understudied. Taking steps to address this gap, our study focuses on Switzerland, where mobility restrictions on exogenously assigned refugees coincide with cantons' autonomy in setting social assistance rates. Linking time-varying cantonal benefit rates between 2009 and 2016 to individual-level administrative data, we find that higher social assistance reduces criminal charges, especially for petty crimes and drug offenses. In light of limited (short-run) repercussions for refugees' labor market participation, our results suggest social assistance can be a cost-effective measure to improve refugee welfare and enhance public safety.
Ongoing
Path2Work: Targeted support of job search for refugees using an online job platform
With Mirjam Bächli, Dominik Hangartner, Rafael Lalive
Incentive or Impediment? The Short- and Long-Term Impact of Low Welfare Support on Refugee Integration
With Dominik Hangartner, Selina Kurer, Michael Siegenthaler
Peer-reviewed Publications
Ahrens, A., Hansen, C.B., Schaffer, M.E. and Wiemann, T., 2025. Model Averaging and Double Machine Learning. Journal of Applied Econometrics, 40: 249-269. ↪Link
Ahrens, A., Stampi-Bombelli, A., Kurer, S., Hangartner, D., 2024. Optimal treatment allocation using policy trees: An application to immigrant naturalization. Journal of Applied Econometrics, 39(7). ↪Link
Ahrens, A., Casalis, M., Hangartner, D., Sánchez, R., 2024. Cash-Based Interventions Improve Multidimensional Integration Outcomes of Venezuelan Immigrants. World Development, 181 106658. ↪Link
Ahrens, A., Hansen, C.B., Schaffer, M.E., Wiemann, T., 2024. ddml: Double/debiased machine learning in Stata. Stata Journal, 24(1). ↪Link
Ahrens, A., Hansen, C.B., Schaffer, M.E., 2023. pystacked: Stacking generalization and machine learning in Stata. Stata Journal, 23(4), pp.909-931. ↪Link
Ahrens, A. and Lyons, S., 2021. Do rising rents lead to longer commutes? A gravity model of commuting flows in Ireland. Urban Studies, 58(2), pp.264-279. ↪Link
O’Toole, C., Martinez-Cillero, M. and Ahrens, A., 2021. Price regulation, inflation, and nominal rigidity in housing rents. Journal of Housing Economics, 52, p.101769. ↪Link
Ahrens, A., Hansen, C.B. and Schaffer, M.E., 2020. lassopack: Model selection and prediction with regularized regression in Stata. The Stata Journal, 20(1), pp.176-235. ↪Link ↪arXiv
Ahrens, A., FitzGerald, J. and Lyons, S., 2020. Commuting across the Irish border. Economics Letters, 190, p.109060. ↪Link
Ahrens, A. and Bhattacharjee, A., 2015. Two-step lasso estimation of the spatial weights matrix. Econometrics, 3(1), pp.128-155. ↪Link
Ahrens, A., Kovandzic, T.V. and Vieraitis, L.M., 2015. Do execution moratoriums increase homicide? Re-examining evidence from Illinois. Applied economics, 47(31), pp.3243-3257. ↪Link
For a full list, see ↪Google Scholar