Laissez-faire or policing social networks?

June 3, 2020

#4 worldwide in 2019 QS ranking Masters in Business Analytics

September 26, 2018

Et si on réinitialisait les réseaux sociaux

September 23, 2018

Beware of weak links in large datasets

August 7, 2018

Data Science and Artistic Creation

January 12, 2018

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June 3, 2020

The debate between Twitter and Facebook on whether they should police the content of posts is need to be understood in the context of 

  1. the mechanisms social network companies use to rank contributions and disseminate information

  2. the specificity of US regulation of publishers and media content providers

I wrote three articles (in French) in Libération and La Libre Belgique in 2016-19 that help to shed some light. 

Libération in 2016: Des algorithmes dangereux pour le débat démocratique

Libération in 2018: Et si on réinitialisait les réseaux sociaux ?

La Libre Belgique in 2019: Stop à l'anarchie sur les réseaux sociaux

September 23, 2018

Ma nouvelle tribune dans Libération traite des problèmes de diffusion de l'information dans les réseaux sociaux et de la création de bulles (qui correspondent à des équilibres locaux). J'y propose une solution pour éviter la dépendance à l'historique (path dependence). 

Les références principales sont:

Nimark, Kristoffer P. (2014). "Man-Bites-Dog Business Cycles." American Economic Review, 104 (8): 2320-67.

Chevillon, Guillaume, Alain Hecq and Sébastien Laurent (2018) "Generating univariate fractional integration within a large VAR(1)." Journal of Econometrics, 204 (1), 54-65. 

August 7, 2018

One of the main characteristics of the last few years is the increasing availability of statistical information on many aspects of individual decisions and participation to economic and financial life. This has become a boon to statisticians as the basis of data-based inference, estimation of models and forecasting has been, since the advent of statistical tools that more data (more evidence) is better than less data.

Firms that harness the potential of large datasets are more at ease to evaluate the relevance of their policy decisions, the risks they incur and their consequences.

Yet, this is not so simple, an argument showing how increasing data availability does not lead to better statistical decision making can be traced to the work of Benoît Mandelbrot (e.g....

September 25, 2017

LORENZETTI, Ambrogio -- Allegory of the Good Government (detail) -- 1338-40 -- Siena

As part of the series of lectures my colleagues and I give to our Master students on Contemporary Economic Challenges, I'm talking tomorrow about Monetary Policy. 

How do authorities conduct a monetary policy to achieve price stability?

Ensuring economic growth, low unemployment and price stability are the three main objectives
that monetary and fiscal authorities target with the help of macroeconomic theory. Controlling
inflation is nowadays mostly in the hand of independent monetary authorities: their aim is to
allow private agents to engage in economic activities and investments without fear for the
future. This lecture reviews the mechanisms presiding over the determinati...

April 19, 2017

Our paper with Sophocles Mavroeidis just got published in the Journal of Econometrics, vol 198(1), 1-9.  It is our second article on the dynamic properties of economic models where agents form expectations using learning. The first one was published in the Journal of Monetary Economics and we also have a third paper, still as a working paper which we recently submitted. 

All papers are available from my Research page. 

In the Journal of Econometrics article, we study learning dynamics in a prototypical representative-agent forward-looking model in which agents’ beliefs are updated using linear learning algorithms. We show that learning in this model can generate long memory endogenously, without any persistence in the exogenous shocks, depending on the weights...

April 19, 2017

On March 14, I participated in a roundtable discussion and Q&A sessions following the Edgar Morin MOOC on Complexity and Decision. The video is above. 

March 2, 2016

   Mon intervention aujourd'hui sur France Info ("un jour une question" par Emmanuel Davidenkoff, en réécoute ici) porte sur l'effet Joseph.


Il s'agit d'un phénomène de persistance sur de très longues périodes, de tendances de long terme qu'on appelle "Longue Memoire". Le nom "effet Joseph" a été proposé par Benoît Mandelbrot, le père des factales, car aux phénomènes de longue mémoire sont associés des mouvemements Browniens fractionnaires. Joseph était un esclave hébreu qui a interprété le rêve de Pharaon de sept vaches grasses chassées par sept vaches maigres: ce rêve correspondait à sept années de récoltes fastes suivies de sept années de disette. Il est lié à la périodicité de long terme des crues du Nil (car les crues permettaient d'enrichir les berge...

January 18, 2016

Ma "mise en boîte de la complexité"

Chaire ESSEC Edgar Morin



Les mégadonnées, ou Big Data, constituent un nouvel outil à la disposition des entreprises et des chercheurs. Pour qu’elles soient utilisables de manière effective pour la prévision, il est essentiel de prendre du recul et de comprendre leur spécificité. Deux éléments les caractérisent : (i) ces données mesurent une activité d’origine humaine (ii) elles ne sont pas, pour la plupart, issues d’expériences contrôlées et reproductibles, mais au contraire, ont été enregistrées au fil de l’activité et constituent donc une référence historique.

Lors de leur analyse et de la modélisation de leur pouvoir prédictif. Nous devons par conséquent répondre à trois questions : quels sont les comportements re...

October 27, 2015

An interesting Legacy


Over a decade ago, James Martin, the highest-selling author of books on computing and related technology gave £60 millions to the University of Oxford to set up a School for the 21st Century. 


James Martin had written over 104 textbooks than any other person – 104, many of which have been seminal in their field. The revenue from his books and associated lectures and videos provided the funds for establishing the Oxford Martin School at Oxford University.