Editorial Spotlight: Léonard Moulin

Léonard Moulin is a researcher in economics at the French Institute for Demographic Studies (INED) in Paris. His research focuses on inequalities in educational trajectories: how they emerge how they accumulate over the life course and how public policies can reduce or reinforce them. His PhD dissertation on tuition fees in higher education received several awards. He has served as an Academic Editor at PLOS One since 2024.

Why is your research on social inequalities in education important to you?

Education is often presented as the great equalizer, and I have always been struck by how rarely that promise survives close scrutiny of the data. I came to the subject through tuition fees, during my PhD: I wanted to understand how their introduction affects access, trajectories and success in higher education.

Since then, I have gradually widened the lens, both upstream and downstream of that first object: I have looked at trajectories from secondary school onwards, at the role of private schooling and at the effects of grade retention. I have also studied how the COVID-19 pandemic weighed on students’ learning and educational choices, as well as on university dropout and entry into the labor market. Most recently, a seemingly distant field, urban mobility policies, brought me back to school: in Milan, the “Area C” limited traffic zone, by reducing pollution in the city center, improved the academic performance of elementary school students, and first and foremost those from disadvantaged backgrounds. A traffic policy that reduces learning inequalities: it says a great deal about how much educational inequalities also play out outside school.

Ultimately, all these objects tell the same story: education is never a single event, and a trajectory is shaped by the accumulation, year after year, of small advantages and small disadvantages.

As part of a multinational research project, what advice would you give other researchers about collaboration?

I am currently a co-investigator on LINEup, a Horizon Europe project that brings together 14 partners across 6 countries and examines how educational inequalities are built up over the course of school trajectories. The project has two strands: a quantitative one, based on harmonized longitudinal data to compare the mechanisms through which inequalities are reproduced across countries, and a qualitative one carried out in schools, whose design I led.

In a project like this, the first difficulty is not statistical: educational inequalities do not have the same drivers in France, Germany, Greece, Italy, Portugal or Spain. School systems differ, so do the data, and even the categories used to record a student’s background. My advice would therefore be to spend, right from the start, far more time than you would like agreeing on definitions and on what is genuinely comparable, and to fully involve the non-academic partners, those who produce or administer school data as well as those who work with schools on a daily basis. Comparability is built, not assumed.

You also write for the public. Why do you think it’s important for researchers to communicate with wider audiences?

Much of my research bears on very real policy choices. How should higher education be funded, and who should pay for it: the student, their family, the taxpayer? How did the pandemic weigh on students’ learning and choices, all the way to their trajectories at university? What place should private schools have when they contribute to school segregation? These are not abstract questions: societies answer them constantly, through their public policies. On these subjects, everyone has an opinion, and legitimately so: school is an experience everyone has been through, and one that many live through again with their children. But the gap between what we think we know and what the data show can be considerable. Research does not settle the debate; it at least allows it to start from the right facts. That is what drives me to write for the general public as well. There is, first, an obvious point: this research is funded by public money, and people are entitled to know what it finds. But there is also something else: getting to the core of a result, stripping away the jargon, and then watching it take on a life of its own as it gets picked up in a debate, cited in a report, and sometimes weighs on a public decision. That is one of the things that give this job its meaning.

What motivates you to serve as an Academic Editor at PLOS One, and how does this experience complement your work as a researcher?

What drew me to PLOS One is its editorial principle: judging a manuscript on the soundness of the research, not on the novelty of the result. In my discipline, applied economics, many important questions call for nuanced answers, modest effects, sometimes no effect at all. Such results are valuable, for knowledge and for public decision-making alike, yet they struggle to find a home in more selective journals.

On a more personal level, handling manuscripts well outside my own specialty keeps me reading widely, and regularly confronts me with methods and literatures I would never have encountered otherwise. What I enjoy most in this role is supporting authors: finding the right reviewers, those whose comments will genuinely move a manuscript forward, and then watching a paper grow stronger at each stage of the process. The manuscripts I have handled have also taught me a great deal: managing conflicting reviews, distinguishing differences of judgment from genuine methodological concerns; upholding publication ethics; working to tight deadlines. And as an author, I know what waiting costs: I try to make clear and prompt decisions, while paying particular attention to early-career researchers and non-native English speakers.

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