Interview with Julien Grenet from PSE


Julien Grenet is a researcher at the CNRS, an Associate Professor at Paris School of Economics, and one of the founders of the Institut des Politiques Publiques. He is specialised in education economics, public economics and market design. He is known by the general public for his participation in the public debate and the vulgarisation of economic concepts in some media such as France Culture.


He agreed to talk to the magazine about his work as a researcher, the importance for economists to be involved in the public debate and about modern issues that the french educational system is facing today.


Why did you create l’Institut des Politiques Publiques? What are its specificities?

We created l’Institut des Politiques Publiques – IPP – with Antoine Bozio in 2011. It followed a six-year period that Antoine spent in London working for the Institute for Fiscal Studies – IFS, which is our main inspiration for IPP. What was lacking in France was an institute that evaluates public policy, tries to put together the insights of academic research and translates them into policy brief reports targeting a broader audience such as policymakers, journalists and citizens. We felt that there was a very good academic research in public policies existing in France, but most of the results were not really conveyed to the general debate, which is, in my opinion, quite unfortunate. IFS was a good model to import in France. We started small but we have  grown up ever since, trying to cover a broad range of topics that are interesting for the public debate, such as tax policies, education, housing, pension, and environment. We also work on health issues.

What is your opinion, as a researcher, on the role of economists in the public debate?

I do not want to be judgmental on what we should do or not do. There are different ways to contribute to the public debate. From my point of view, you do so through the academic output you produce that then spills over onto the public debate. You should also try to meet policymakers. The important thing is to participate in the debate on topics that you know, and only on them. Unfortunately, it is not always the case, and that sort of attitude may damage the reputation of economists. I am personally trying to restrict my interventions to questions on education or housing, since I have worked on it.

Why did you choose to study education, and more specifically social segregation and selection processes, as your main topic?

I started to study education because it was the topic of my Master thesis. What drove me to this is that I come from a family of teachers whose social mobility upwards was entirely due to school.  I was shocked in a way by the fact that through the education system, my family managed to climb up the social ladder. Today, we sometimes have the impression that it does not play this role anymore, and we wonder what is wrong with our educational system. I think the tools of economists have a lot to say. What we can learn with economics is improving the efficiency of the educational system.

I went into it for personal reasons; afterwards, the topics that I have addressed are more random. I started working on the return of education, which is a very classic question. Then, since I was working in the same office as Gabrielle Fack, who was working on housing, we thought about working on something in between those two fields of interest. We started working on the effect of school zoning (“la carte scolaire” in French) on housing prices. We thought that this system was one way to assign students to schools, but we actually found out there were many others. We started reading about the school choice mechanism and got interested in that. It is a very dynamic field in economics: how to assign students to schools? How to assign teachers to schools? How to drive students to higher education programs?

In France, there has been a lot going on on the subject lately, and this is important for the public debate. We heard a lot about Admission Post Bac and Parcoursup; those are, in my opinion, important technical tools for policy implications or policy effects. We empirically know quite little about how their effect in the real world. I think this is where we, as economists, can contribute: by improving these tools.

According to the OECD, France is one of the most unequal countries in terms of climbing up the social ladder. What is your analysis?

I think that there are many reasons to it; yet, we can hardly identify them. What the OECD has shown is that at the age of 15, your performance is more determined by your social background in France than in any other country. France is typically in the top three countries where social determinism is the strongest at school.

One reason is that our educational system, especially the middle school system – between 11 and 15 years old – is highly segregated. From research, we know that ghetto schools harm students who are studying there beyond the effect of social background. This segregation in the school system increases inequalities. This might be due to different things: the level of residential segregation is very high in France, and the way we assign students to schools is far from being optimal. As we are assigning students to their local school, if the neighborhood is segregated, then the school is going to be segregated too.

There are many other ways to assign students that we could use. For instance, there is what we call “control school choice” that tries to achieve a balance in the social composition. We could also redesign the school boundaries, or “school catchment”, so that they would be more diverse in their intake students. That is one important topic to be addressed: can we reduce segregation in school by using different methods of assignment?

There is also a problem with how teachers are assigned to school. Typically, young teachers, who are inexperienced, are assigned to the most deprived schools in France, which is obviously a problem. We know that teachers have their biggest efficiency improvement during their first few years of teaching. Hence, students from deprived schools have less probability to benefit from the most efficient teaching.

There is also an issue with the educational system. The French system is very good at selecting an elite and the whole system is created to detect these students who go all their way up to “classes préparatoires”, “grandes écoles” and so on. However, it is not so good to have as many students as possible to succeed. We have a very strong elite but, in the meantime, we are losing a lot of students along the way. France has a high drop-out rate: many students quit school with no certification. Another problem with the system is that vocational courses are seen as a personal failure, unlike many other countries. Therefore, a lot of students who follow this path feel like they failed their studies.

Your research focuses on assignment algorithms. What consequences did you find of such algorithms on students’ choices?

France is a very centralised country; hence, it is more inclined to use these algorithms to assign students and teachers than other countries. There has been very little involvement of researchers and economists to design these algorithms. In fact, a lot of research on this assignment mechanism comes from the U.S.. It is a branch of design mechanism theory which received a lot of visibility thanks to the Nobel prize of Alvin Roth and Lloyd Shapley in 2012. They really transformed the landscape in many dimensions:  for example, the assignment of students to school in the U.S. has been completely redesigned in many cities using these algorithms. Kidney exchanges now rely on these algorithms, and there are many new applications, such as social housing allocation.

In France, in my opinion, the main problem is the fact that there is not enough transparency about these algorithms. They exist in order to produce the best possible matching between students and schools, to try to maximize satisfaction while respecting several priority rules. The problem is that, the way the algorithms and the priority rules work are not well known. This has led many people to reject the whole idea of selecting people with algorithms because they feel that there is a black box, like a lottery, when in fact, an algorithm is just a tool.

What really matters is the way you design priorities. If you have two students who apply to a school and there is only one seat left, which student has the priority over the other is a political decision depending on which criteria you promote – students with better grades, students who live closer to the school, students with a lower social background, … This is not sufficiently explained and democratically decided. The issue today is to bring research into these algorithms, so that there are more discussions and a better understanding of the way they work.

You are currently working on a project on social mix. Why it is a topic of interest? What are your preliminary results and your analysis?

We have already said that the lack of social mobility is one of the reasons why there is so little mobility upward in France. The question is how to address this problem. We have several potential ways of doing it. We could use the  , we could redesign the school catchment area, we could also close some schools and send some students away from their original choice, like in the city center rather than in a suburban area.

We do not have many empirical results telling us in which case we should use this or that tool nor do we know the actual effect of some tools on segregation. Moreover, these effects are mitigated by the behavior of the parents: if they decide to send their child to a private school, we might not get as much social mix as we initially wanted. Therefore, we are trying to evaluate different ways to assign students to school in order to create social mix and evaluate their effect. To do so, we are using several experiments that were launched across the country, and we try to compare the effect of these experiments on social mix.

The reason why we want to increase social mix is because we believe it is going to reduce inequalities. We are interested in the effect of social mixing on both students’ performance and their non cognitive aptitudes: their self-confidence, their social fatalism and the way they perceive others – the perception of difference. What we are trying to use here is the fact that, in some experiments, even if we found a large effect on social mix,

We try to evaluate this through surveys that are conducted in schools. We are now proceeding in the second wave; two other waves  are coming. What we try to evaluate is how does the change of the school social composition individually affect the students through their performance in school and their non-cognitive outcomes. If we look at the literature, there is no evidence of this, especially on the non-cognitive aptitudes, because we cannot really measure it with administrative data. We need to go to the schools and directly ask students some questions. That is our contribution to the literature: trying to answer one of these questions.

Finally, what results in your research were you surprised of?

I did not anticipate the fact that this students’ assignment mechanism would have such a big impact on the composition of schools. I started to work on these assignment mechanisms looking at several high schools in Paris. In 2013, the educational authority of Paris adopted an algorithm to replace the manual procedure. As a part of the algorithm, they created a bonus for low-income students. This bonus would increase their priority, and as a result, the social segregation in high schools in Paris went down by 30 % in only two years, which is huge. This had not been anticipated by the local education authority because they did not think that the way the bonus had been created would make that bonus so large. They did not realise that they gave almost automatically their first choice to low-income students. This completely changed the landscape of Paris, which was the most segregated area in France. This is no longer the case.

By working on this data, I realised that these tools are in fact even more powerful than any reform. For instance, the “assouplissement de la carte scolaire” was relaxing these schools’ catchment areas, so that students could apply to schools that are away from their homes. In reality, this had very little effect on the social composition, whereas these school choice algorithms, like the one implemented in Paris, had a huge impact with very little coverage in the media. The numbers shown in the graph are explanatory: the low-income students now have a bigger set of choices than before. This is one of the surprises of research and economics: it is not because something is not looked upon by researchers or does not get any attention, that it is not existing. You can be like an archeologist: you can dig the results up that were unknown until now and they can change the way you see and understand the educational system.


By Thomas Séron

Subsidies to foreign students and French tuition fees

Higher education is more globalised than ever nowadays. Excellent universities emerge in developing countries and institutions thus face an increasing level of competition to attract the best students from all over the world. At TSE, about half of the students are foreigners. One of the obvious reasons why so many international students seek admission in Toulouse — apart from its reputation and academic motives — is  that France is one of the cheapest places to study among developed countries (see, for instance, OECD data on tuition fees). Tuition fees are relatively low for foreign students, and the state offers many scholarships and grants. While such advantages increase the competitiveness of French universities, is it economically justified to offer foreigners so much public funding? In the same vein, why do most governments provide some funding opportunities to their home students who decide to study abroad?

At first glance, the answer to such questions is not clear-cut. On the one hand, subsidising[1] foreign students attracts the best — future — researchers and foreign workers into the country, which increases the circulation of ideas. For instance, between 2008 and 2012, 45% of foreign graduates in the United States extended their visa in order to work in the metropolitan area where they studied (Ruiz, 2014). In the same spirit, financing home students who study abroad encourages them to apply to top universities, which is profitable for the country if they decide to come back to work in their country of origin. On the other hand, subsidised foreign students might choose to go back to their country of origin, and home students might decide to stay abroad after completing their studies. Hence, one could think that the money invested in such areas is somewhat wasted, and make foreigners pay for their education would be better. In the light of the recent announcement of the “Bienvenue en France” (“Choose France”) policy project, which aims to attract more international students, the rise of tuition fees for non-EU citizens could be based on such argument.

Are international students beneficial for an economy?

It is difficult to measure precisely if a country is a “net winner” of higher education globalisation, but one main topic in the literature is to determine whether admitting more international students leads to crowd-out domestic students. Universities having a limited budget admitting more foreigners might reduce the number of spots available for home students. However, empirical evidence shows the opposite: admitting more international students — especially for graduate programs — has a strong crowd-in effect because universities can collect more tuition fees. In the United States and the United Kingdom, estimates of this effect lie around 0.8, meaning that admitting one more foreign graduate student leads to almost one more domestic student enrolled (Machin and Murphy, 2017; Shih, 2018). This fact may also reflect some intangible benefits of the rapid increase in foreign students’ enrollment in developed countries such as higher exposition to international peers and extension of the domestic students’ network (see Winkler, 1984).

This argument is particularly interesting because it means that attracting more foreign students is a good national policy to favor post-secondary education among the domestic population. Also, as another form of externality, a country that offers substantial subsidies to foreigners might benefit from an easier access of its domestic students to foreign education systems. As an example, most — if not all — countries of the European Union offer lower tuition fees and more scholarship opportunities to EU citizens. In a recent study, an Italian researcher also found a positive link between Latin American students’ enrollment and trade between OECD countries and the students’ country of origin (Murat, 2018).

On the cost side, there is no clear answer to whether the benefits of attracting foreigners offset the costs of financial support offered by the host country. There is only little evidence that subsidising education of foreign students leads to an increase in steady state economic growth (see Bergerhoof et al., 2013). Nonetheless, it seems reasonable to think that there exists somehow a net gain considering that subsidising foreigners is a widely spread practice.

Choose France, but pay more.

On 19th November 2018, French Prime Minister Édouard Philippe announced the new national strategy to attract international students. The policy project aims at giving a boost to the growth of the number of international students, that is lower than in other developed countries who adopted more “offensive policies” in this regard such as Germany, China, and Canada. The controversial policy mostly consists in raising tuition fees of non-EU international students in order to finance more generous scholarships. If the plan is adopted, the annual tuition will increase to 2,770€ at the Bachelor level. At the Master and PhD levels, international students will have to disburse 3,770€ per year. It seems quite counter-intuitive that the government expects to attract more students while also increasing tuition fees. Indeed, the low price of higher education is the comparative advantage of France over North American and some other European countries right now. With only one-quarter of the student population being eligible for some fundings from the government, this increase in tuition fees should crowd-out foreign students. Some African students (who comprise about half of the foreign students population in France) already expressed concerns about whether they would be able to finance their studies if the new policy is implemented.

At TSE, admission committees are well aware of that; in order to keep the competitiveness of the School unchanged, the institution will need to compensate graduate students for this increase. In other words, the new policy will partly consist in simply taking money out of the universities given that at least some institutions will increase scholarships so that their students would not have to bear all the cost of the government’s decision. Without such compensations, it is likely that many students will think twice before seeking admission in France. Therefore, this policy should have two perverse effects that are contrary to the idea behind it: international students’ enrollment should not substantially increase — it might as well decrease — and some of the generated revenues from the government will be extracted from universities’ budget. Apart from taking money from “those who can afford it”— which I doubt —  I do not see how this policy does any good nor encourages students to choose France.

by Sébastien Montpetit

[1] The term “subsidies” will refer to both low tuition fees and availability of scholarships, loans, and grants.

Why slides are not a good way to teach

Have you ever fallen asleep during a course in which the teacher only uses slides as material? Do not worry, you are not alone. The majority of students cannot fully pay attention if the professor is just pointing at bullet points with a laser pen. This article will discuss why this system is so common and why it is often a bad idea.

So, what is the problem? First of all, attending the class becomes extremely boring. For an hour, slides continue passing by on the whiteboard. Teachers continue repeating what is written on slides while students are struggling to stay awake. This scene becomes even more exacerbated by the fact that the slides’ design is standardised, so every course becomes a copy of the next one.

Furthermore, slides lack specificity and detail. Explaining complex ideas becomes difficult as it is just a summary with bullet points and dashes. Students expect to find every detail and often get stuck on complicated problems because an explanation is not provided.

Last but not least, teachers do not explain as well when they are just talking as when they are also writing it down at the same time. Not having a PowerPoint presentation forces them to start their reasoning from scratch. This makes a detailed explanation a lot more coherent. It is also much easier for teachers to point out details and to highlight important points on a blackboard compared to using a laser pen.

So why do we still use slides for teaching? I think there are two main reasons. First of all, it requires a lot less effort from the professor during class. Secondly, and more importantly, it is also a lot easier for students because they do not have to take notes. They feel reassured about getting a minimum of the content of the course. However, learning becomes a lot easier if you have taken notes during class. During the process of writing down, the brain can already reflect on the content. This increased effort thoroughly facilitates the learning process. As learning is generally linked with effort, writing is an efficient way to memorise and to understand.

However, some research shows a more nuanced view. A 2006 paper written by David Levasseur shows that computer-generated slides are an effective medium of teaching when students can print the slides before the course so that students spend less time writing and more time listening. It is based on the fact that, as students have the lecture content, they do not worry about missing something and pay more attention to explanation given by the professor. This allows for more interaction between the professor and the students. Finally, the research review concludes that the class must switch between several ways of learning styles: verbal, written, and visual.

Recently, a professor in computer science at the University of Auckland became famous for an article on why universities should banish PowerPoint presentation when teaching. According to him, using slides tends to diminish the students’ learning. However, universities will not ban slides for a simple reason. They measure success by the students’ satisfaction rather than learning outcomes. As long as they continue to use satisfaction as a primary metric, they will not abandon the use of slides.

In a nutshell, using slides in class negatively affects learning in class. It is both damaging for students and professors, as understanding complex reasonings becomes problematic. However, slides can be used as an additional medium to create more interaction between students and professors. Finally, students must learn to not always ask for slides. They must try to interact during class by participating and asking questions.

by Vincent Larrieu