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Achim Ahrens

@aahrens

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/

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Latest posts by Achim Ahrens @aahrens

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.

05.04.2025 11:44 ๐Ÿ‘ 2 ๐Ÿ” 0 ๐Ÿ’ฌ 0 ๐Ÿ“Œ 0
Introduction

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/

05.04.2025 11:38 ๐Ÿ‘ 3 ๐Ÿ” 1 ๐Ÿ’ฌ 1 ๐Ÿ“Œ 0
Preview
Migration, Refugees, and Asylum Seekers Data Explorer Explore the migration of people across the world.

See how immigration numbers compare across countries: https://ourworldindata.org/explorers/migration

08.11.2024 17:43 ๐Ÿ‘ 12 ๐Ÿ” 4 ๐Ÿ’ฌ 0 ๐Ÿ“Œ 0

could you add me?

27.11.2024 09:10 ๐Ÿ‘ 0 ๐Ÿ” 0 ๐Ÿ’ฌ 1 ๐Ÿ“Œ 0

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.

27.11.2024 09:04 ๐Ÿ‘ 4 ๐Ÿ” 0 ๐Ÿ’ฌ 0 ๐Ÿ“Œ 0
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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....

27.11.2024 09:04 ๐Ÿ‘ 6 ๐Ÿ” 3 ๐Ÿ’ฌ 1 ๐Ÿ“Œ 0
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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...

27.11.2024 09:04 ๐Ÿ‘ 3 ๐Ÿ” 0 ๐Ÿ’ฌ 1 ๐Ÿ“Œ 0
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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

27.11.2024 09:04 ๐Ÿ‘ 10 ๐Ÿ” 3 ๐Ÿ’ฌ 1 ๐Ÿ“Œ 0
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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...

27.11.2024 09:04 ๐Ÿ‘ 6 ๐Ÿ” 2 ๐Ÿ’ฌ 1 ๐Ÿ“Œ 0
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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....

27.11.2024 09:04 ๐Ÿ‘ 7 ๐Ÿ” 2 ๐Ÿ’ฌ 1 ๐Ÿ“Œ 0

Now that we are (almost) all here and the year is coming to an end, it's a good time for a personal annual recap.

๐Ÿงต A thread of 5 papers. Keep reading for labor, migration, applied econometrics, double machine learning.

(Coincidentally, I am looking for a job. #Econbsky #EconSky)

27.11.2024 09:04 ๐Ÿ‘ 10 ๐Ÿ” 5 ๐Ÿ’ฌ 1 ๐Ÿ“Œ 0

Could you add me? Thanks for doing this

21.11.2024 19:06 ๐Ÿ‘ 0 ๐Ÿ” 0 ๐Ÿ’ฌ 1 ๐Ÿ“Œ 0

pystacked is joint work with @markeschaffer.bsky.social
and Chris Hansen.

For more info, see statalasso.github.io/docs/pystack....

07.01.2024 15:56 ๐Ÿ‘ 1 ๐Ÿ” 1 ๐Ÿ’ฌ 0 ๐Ÿ“Œ 0

Our open-access article introducing -pystacked- for stacking and machine learning in Stata is now available online. doi.org/10.1177/1536...

Watch our short video to see what -pystacked- can do. youtu.be/MVAlpcfIfxA

07.01.2024 15:56 ๐Ÿ‘ 11 ๐Ÿ” 4 ๐Ÿ’ฌ 1 ๐Ÿ“Œ 1