December 6th, Celia Ruiz-Mejia's PhD Defense

December 06, 2021 Research

 Celia Ruiz-Mejia will defend her thesis on Monday 6 december 2021 at  2 PM (CET) via Zoom
Please contact Elvire JALRAN to attend the meeting.

Title: Essays in labour, transport, and urban economics

Supervisor: Marc IVALDI
Memberships are:

  • Miren Lafourcade, University Paris-Saclay (RITM)
  • Adelheid Holl,Spanish National Research Council (CSIC, Institute of Public Goods and Policies)
  • Ana Gazmuri, University Carlos III Madrid - Toulouse School of Economics
  • Karine Van-Der-Straeten, CNRS Senior Researcher, Toulouse School of Economics
  • Marc Ivaldi, Senior Researcher, Ecole des Hautes Etudes en Sciences Sociales, Toulouse (EHESS)


My PhD thesis consist of three chapters. The first chapter has the objective of studying the impact of labour market access inequalities on local unemployment rates. The second and third charters have the objective of studying the role of transport on the distribution and evolution of several employment outcomes.

Regarding the first chapter, I study the effect of accessibility to job opportunities on individuals’ probability to find a job. I make use of a complex micro-data infrastructure combining individual job-seekers’ registrations in unemployment with a new sector- and location-specific accessibility index. Indeed, the main result suggest that, if an individual job-seeker moves from a municipality in the 10th percentile of the accessibility distribution to a municipality in the 90th percentile, her probability to find a job increases by 5%. Further, this impact is significantly different across education and skills groups, where low educated and low skilled job-seekers are significantly more affected than their educated and skilled counterparts. This result points at a higher ability of the later to move across labour markets. This result has important policy implications. Indeed, it points at the necessity of policies fostering the mobility of the most vulnerable job-seekers, to increase their probability of re-entering the labour market.

Regarding the second and third chapters, they focus on the European city of Toulouse, and they investigate the role of transport on employment, population, and productivity. Particularly, the second chapter investigates the role of transport infrastructure and agglomeration externalities on some major changes experienced by the city of Toulouse in the recent years, i.e., a departure of population and employment from the city centre, and a steeper increase of employment and wages in the suburbs. The most important results suggest that, firstly, transport infrastructure significantly impacts the location of employment and population. Secondly, transport infrastructure foster employment growth, especially in the suburbs, implying that infrastructure promote the decentralization of employment. Finally, agglomeration externalities only exist within areas close to employment concentrations, and the highest externalities are found in the suburbs, suggesting that the emergence of agglomeration externalities plays a crucial role in the economic development of the suburbs.

In the third and last chapter of my thesis, I focus on estimating the extent of agglomeration externalities, and the direct and indirect impacts of transport exposure on the productivity structure of the city of Toulouse. I take advantage of a rich database combining very fine georeferenced data on employment and transport networks, and I recover the productivity effects of agglomeration and transport measures by the implementation and estimation of a wage determination model. The results suggest that both agglomeration and transport exposure measures have a substantial and significant impact on local productivity. Indeed, when density of employment doubles, productivity increases by 1.6%. Further, the effects of transport exposure measures differ for the two modes considered, private vehicle and public transport. In both cases, a higher exposure to transport supply implies higher levels of employment and productivity.