How did you come to choose your research topic?

My journey as a migration researcher began when I joined the National Center of Competence in Research (NCCR) for Migration and Mobility Studies (NCCR – On the Move) as a doctoral student. The interdisciplinary nature of migration research allowed me to exchange ideas on migration and mobility in Switzerland and beyond with researchers from diverse fields, including social sciences, economics, and law.

At the NCCR – On the Move, I joined the project Migration and Labor Market Inequality under the supervision of Professor Martina Viarengo, my thesis advisor, and Professor Tobias Müller (University of Geneva). This project examines the relationship between inequality and migration, focusing on the factors that shape labour market inequalities on both the demand and supply sides. My subproject specifically analysed the gender dimension of labour market outcomes for migrants.

And what about the thesis project itself?

The overarching theme of my PhD dissertation is the labour market integration of migrants in Europe, which I explored in three essays through three key lenses: gender, education, and health. These dimensions are essential for understanding the diverse experiences of migrants and their long-term integration outcomes. Migration economists frequently face a disconnect between theoretical models and the real-world phenomena they aim to explain, but fortunately the availability of high-quality data and advanced identification strategies for studying causal relationships enabled me to bridge this gap as I was able to leverage internationally comparable microdata sets and adopt multiple perspectives to address my research topic.

Can you describe each essay?

In the first essay, “The Gender Aspect of Migrants’ Assimilation in Europe”, co-authored with Professor Martina Viarengo and Professor Giovanni Peri (UC Davis) and published in Labour Economics, we used the EU Labour Force Survey (EU-LFS) to estimate the degree of immigrants’ labour market assimilation, measured by the probability of being employed by gender, across 16 European countries between 1999 and 2018. The results indicate that, in most countries, female migrants start with a larger employment gap but converge more rapidly than male migrants. However, we observe significant variations across countries. To examine the sources of these variations, we analysed correlations between our estimates and country- and region-level macroeconomic, institutional, and cultural variables. While we do not identify very significant correlations at the national level, we find a strong correlation between attitudes towards migrants and their employment convergence across subnational regions.

In the second essay, “Effect of Compulsory Schooling Reforms on Migrants in Europe”, I used the cross-sectional version of the EU Statistics on Income and Living Conditions (EU-SILC) to estimate the differential impacts of education on labour market outcomes for natives and second-generation migrants in 19 European countries. Recognising the endogeneity of education in the Mincerian equation, I employed changes in the length of compulsory schooling as an exogenous instrument to estimate a two-stage least squares (2SLS) model. First, I identified the specific reforms affecting each population group, finding that no single reform simultaneously impacted both groups. I then compared the effects of additional schooling on labour market outcomes, discovering that while some reforms led to notable increases in the average years of schooling among migrant populations, the returns to education for migrants remained limited.

In the third essay, “Health Shocks and Migrants’ Labor Market Outcomes”, I used data from the European Community Household Panel (1994–2001) to construct treated and control groups. Using propensity score matching, I estimated the average treatment effect on the treated (ATT) of a health shock – defined by individuals’ subjective health status – on migrants’ labour market outcomes. The results suggest a significant causal effect of health shocks on the probability of migrant employment, which is stronger than the effect on natives’ employment. The estimated effects vary across countries, with the largest decrease in migrant employment observed in Portugal.

What could be the social and political implications of your thesis?

International migration influences various aspects of life, and understanding the complexities of migrant integration requires an in-depth analysis of key factors such as gender, education, and health. Each paper in the thesis provides a unique contribution regarding these factors.

A key finding across all studies is the significant heterogeneity of results across countries. An important takeaway is that these differences may be explained by variations in institutional frameworks and unobserved (or imperfectly observed) characteristics of immigrant populations.

The findings emphasise the need for tailored education policies targeting migrant populations to address persistent labour market gaps between natives and migrants. Similarly, health policies and labour protections should be adjusted to better support migrants during periods of ill health, reducing their risk of labour market exclusion.

By addressing these dimensions, this dissertation provides deeper insights into the socio-economic integration of migrants and the policies that can support their long-term success. The research contributes to a more nuanced understanding of migration, offering valuable evidence for policymakers and scholars alike.

What are you doing now?

Since February 2023, I have been working with the International Migration Division at the OECD. In this role, I have been involved in two projects. The first is the compilation of the Database on Immigrants in OECD and non-OECD countries, which is based on census data and includes information on socio-economic characteristics and labour market outcomes by detailed place of birth. The second is the OECD Migration Anticipation and Preparedness Task Force, where we work on medium-term forecasting of migration flows across various categories (e.g., border crossings, asylum applications, family reunification, international students, and labour migration) in member countries.

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Taehoon Lee defended his PhD thesis in Development Economics, titled “Three Essays on Migrant Assimilation in Europe”, on 25 September 2024. Assistant Professor Yuan Zi presided over the committee, which included Associate Professor Martina Viarengo, Thesis Director, Professor Ugo Panizza, and, as External Reader, Professor Frédéric Docquier, Vice-Executive Director and Leader of the Research Programme on Crossing Borders, Luxembourg Institute of Socio-Economic Research (LISER).
Readers interested in the PhD thesis can contact Taehoon Lee.

Banner image: Shutterstock/Barry Barnes.
Interview by Nathalie Tanner, Research Office.