Achim Ahrens
aahrens.bsky.social
Achim Ahrens
@aahrens.bsky.social
Senior Researcher, @immigrationlab.bsky.social, ETH Zurich | AP CERGE-EI from Sept '25 | Software: http://statalasso.github.io | Applied econometrics, ML, migration, labour | https://achimahrens.de/
If your main problem is not many controls but many proxies of public transit, then I would bunch them together into 1 variable using PCA or factor analysis, as Peter suggests.
April 5, 2025 at 11:44 AM
If lasso, PDS-lasso is what you want to do. You need to consider both the outcome and treatment equation. Even better: use DDML; then, you can relax sparsity and consider other learners. Stata packages: pdslasso, ddml. R: ddml, DoubleML, hdm.
statalasso.github.io thomaswiemann.com/ddml/
Introduction
statalasso.github.io
April 5, 2025 at 11:38 AM
Reposted by Achim Ahrens
See how immigration numbers compare across countries: https://ourworldindata.org/explorers/migration
Migration, Refugees, and Asylum Seekers Data Explorer
Explore the migration of people across the world.
ourworldindata.org
November 8, 2024 at 5:43 PM
could you add me?
November 27, 2024 at 9:10 AM
Many,many thanks to: @danielauer.bsky.social, @andreasbeerli.bsky.social, Alessandra Stambi-Bombelli, Marine Casalis, Dominik Hangartner, Chris Hansen, Selina Kurer, Stefanie Kurt, Rodrigo Sanchez, @markeschaffer.bsky.social, Michael Siegenthaler, Michaela Slotwinski, Alois Stutzer, Thomas Wiemann.
November 27, 2024 at 9:04 AM
5 - Focusing again on Switzerland, we find that higher social assistance reduces criminal charges, especially for petty crimes and drug offenses.

WP: papers.ssrn.com/sol3/papers....
November 27, 2024 at 9:04 AM
4 - What is the effect of cash assistance on the socio-economic integration of vulnerable Venezuelans living in Peru? We evaluate a cash-based intervention implemented by IOM and partners.

Published World Development: doi.org/10.1016/j.wo...
November 27, 2024 at 9:04 AM
3 - Double Machine Learning (DML) has become hugely popular for estimating structural parameters using ML. We highlight the risk of employing ill-suited machine learners and show the benefits of pairing DML with model averaging. With R & Stata software.

Accepted @ JAE: arxiv.org/pdf/2401.01645
November 27, 2024 at 9:04 AM
2 - Linking the labor market restrictions faced by refugees in Switzerland to the literature on outside options, we find that restricting refugees' outside options reduces job-to-job mobility and refugees' wages, widening the wage gap to natives in similar jobs.

WP: osf.io/preprints/so...
November 27, 2024 at 9:04 AM
1 - How can we encourage eligible immigrants to naturalize? We design and field a policy tree for a letter-based information campaign. The policy tree optimally selects between alternative encouragement letters.

Forthcoming JAE: doi.org/10.1002/jae....
November 27, 2024 at 9:04 AM
Could you add me? Thanks for doing this
November 21, 2024 at 7:06 PM
pystacked is joint work with @markeschaffer.bsky.social
and Chris Hansen.

For more info, see statalasso.github.io/docs/pystack....
January 7, 2024 at 3:56 PM