Chloé Maisonnave is one of the top-ranked winners of the EMOS Master’s thesis competition 

“Interactions within a multi-layer EU inter-bank network”, Chloé Maisonnave’s final year thesis, has been awarded a prize among 24 submissions from students of 12 different Master’s in the EMOS network, a label awarded by Eurostat. The winner, a graduate of ENSAI’s Master in Data Science for Public Decision Making, has been invited to present her work before an audience of researchers and statisticians, at the next NTTS conference, in Brussels

This competition, intended for graduates of the EMOS (European Master of Official Statistics) network, highlights official statistics as a research topic and values the innovative contributions of young talents. Since its creation in 2019, this biennial event has always included ENSAI graduates. According to the jury of the latest edition, the overall quality of the applications was unanimously praised.

Chloé, many EMOS Masters students choose to do an internship at a National Statistical Institute. In this sense, your choice to integrate the European Central Bank (ECB) for an internship at the end of your studies stands out: what motivated it?

Chloé Maisonnave: I absolutely wanted to do my end-of-study internship outside of France to live abroad for a few months; it was an experience I had never had before. During my schooling, I never felt the desire or the need to go live in a foreign country. It was when I saw all the possibilities offered by ENSAI that I said to myself: “and after all, why not?” Also, I had already had the opportunity to work in national and regional public statistics organizations during my first- and second-year internships at ENSAI. All I needed was to tick the European statistics box! So, I approached Eurostat and the ECB through the school’s alumni directory. I quickly had a particularly good connection with my contacts at the ECB who suggested an interesting and innovative internship subject, which could allow me to acquire new skills but also to apply the knowledge learned from ENSAI and my Master 2.

Let us take a closer look at this internship: what did you work on, for how long, and with which team?

C.M.: My internship lasted five months in total: one month remotely because of the Covid pandemic and four months on site, at the Japan Center in Frankfurt am Main, Germany. I was warmly welcomed in the ECB Data Office, a section of about 15 people attached to the Directorate General Statistics (DGS) of the ECB.

The subject of my internship “Interactions within a multi-layer EU inter-bank network” was a continuation of a project that started in 2020; this project aims at integrating new granular databases in finance built from a common European framework, with the objective of facilitating statistical analyses. My mission was to extend this project by adding a temporal dimension and by developing statistical models that could explain the interconnections between banking groups over time in a network composed of several layers.

My work was structured around three phases: documentation, database integration, and statistical modeling. My internship gave me insight into the steps and logic of research work; in particular, the Network theory being new for me, I had to provide a significant bibliography work. I was therefore able to acquire new theoretical knowledge on this subject, but also to consolidate certain foundations in coding, especially in PySpark and Python. Moreover, an important detail: I carried out my internship entirely in English, whether in the exchanges with my supervisor and my colleagues, the writing of my thesis, or my defense: I noticed real progress, mainly in my oral fluency.

Finally, the very European environment of the ECB and Frankfurt offers a cultural opening; my internship at the ECB would not have been the same if it had not been enriched by numerous meetings, trips, and discoveries. So, it was an extremely positive experience, which makes me want to repeat the experience in another statistical organization in Europe or even internationally.

The Master thesis you wrote on this internship won first prize in the competition. The subject is complex, but could you summarize it in a few sentences?

C.M.: My thesis aims to evaluate the impact of the position of European banking groups in relation to each other in a network on systemic risk and financial stability. Many indicators can be used to describe the topology of a network. I therefore used these indicators to study the evolution of the topology of European bank networks over time, notably during the Covid-19 crisis, and on several interbank markets such as, for example, the long-term loan market. I am interested in the notion of centrality: a bank is considered central if it carries out many financial transactions with other banks. So, a question arises as to whether the fact that a bank is central in the network accentuates the impact that this bank would have in case of default.

What are the reasons why you accepted to have your thesis submitted by the ENSAI selection committee?

C.M.: Competing for the best EMOS thesis is an opportunity to compare one’s work with that of other students with similar academic backgrounds, and to see how this work can be perceived by a committee of statisticians and researchers.

Beyond the academic recognition, the challenge was also to be able to participate in the NTTS conference; which will allow me to perceive a new research angle of European statistics.

It is both an opportunity to discover innovative topics and methods in statistics, but also to bring into light the subject on which I worked.

Let’s go back a bit: why did you choose ENSAI and more specifically the public statistician program?

C.M.: After my scientific baccalaureate, I went to a B/L preparatory class, with an emphasis on literature and social sciences. There I discovered economics and sociology, which I liked very much: among them, inequalities, redistribution, culture and … public policies. So, I enrolled at ENSAI as a public statistician with the idea of producing indicators and using statistical methods to inform public decision-making. In parallel to my second year at ENSAI, I followed a Bachelor’s degree (“Licence 3”) of Economics in the Grandes Écoles program at Université Paris Dauphine-PSL. During my third year, I traveled a lot between Ker Lann and Place Hoche in Rennes to attend the courses of the Master 2 Data Science for Public Decision Making, majoring in Statistical Studies.

What is your current position? What are your main missions?

C.M.: In September 2022 I started a position at Dares, the French ministerial statistical service of labor, as a territorial studies officer on employment policies. My job consists of evaluating territorial public policies on work integration schemes. More specifically, I am working on the evaluation of the “Emplois francs” program via a survey. With my colleagues, I followed up on the pilot of the survey as well as the coordination with our service provider in charge of the collection from the establishments and made the necessary adaptations to improve the survey before the main fieldwork. I also wrote a file submitted to the Label Committee to obtain the label of general interest and statistical quality with a request for its mandatory nature.

My second mission is the evaluation of the “Territoires Zéro Chômeurs de Longue durée” (Zero Long-Term Unemployed) experiment. We are currently preparing the governance of this evaluation in collaboration with France Stratégie. In a few words, it is a matter of coordinating with qualified people and administrations to form a committee that is in charge of evaluating the experimentation; it is thus necessary to clearly define the roles and subjects of each one.

Learn more about the EMOS Master’s thesis competition and about ENSAI’s Master in Data Science for Public Decision Making