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Départements : Economie et Sciences de la décision, GREGHEC (CNRS)

Nudge is a concept of policy intervention that originates in Thaler and Sunstein's (2008) popular eponymous book. Following their own hints, we distinguish three properties of nudge interventions: they redirect individual choices by only slightly altering choice conditions (here nudge 1), they use rationality failures instrumentally (here nudge 2), and they alleviate the unfavourable effects of these failures (here nudge 3). We explore each property in semantic detail and show that no entailment relation holds between them. This calls into question the theoretical unity of nudge, as intended by Thaler and Sunstein and most followers. We eventually recommend pursuing each property separately, both in policy research and at the foundational level. We particularly emphasize the need of reconsidering the respective roles of decision theory and behavioural economics to delineate nudge 2 correctly. The paper differs from most of the literature in focusing on the definitional rather than the normative problems of nudge.

Mots clés : nudge, liberal paternalism, policy analysis, behavioural economics, decision theory, rationality, decision biases, Thaler and Sunstein, Kahneman and Tversky

  • ECO/SCD-2016-1182
  • Economics: Between Prediction and Criticism
  • I. GILBOA, Andrew POSTLEWAITE, Larry SAMUELSON, David SCHMEIDLER

Départements : Economie et Sciences de la décision, GREGHEC (CNRS)

We suggest that one way in which economic analysis is useful is by offering a critique of reasoning. According to this view, economic theory may be useful not only by providing predictions, but also by pointing out weaknesses of arguments. It is argued that, when a theory requires a non-trivial act of interpretation, it's roles in producing predictions and offering critiques vary in a substantial way. We offer a formal model i which these different roles can be captured.

Mots clés : Methodology, Models, Economic Modeling

  • ECO/SCD-2016-1162
  • The Signaling Effect of Raising Inflation
  • J. BARTHELEMY, E. MENGUS

Départements : Economie et Sciences de la décision

This paper argues that central bankers should raise inflation to signal their credibility to forward guidance policies. As inflation can be stabilized in normal times either because of central banker's credibility (e.g. because of reputation concerns) or because of his aversion to inflation, the private sector is unable to infer the central banker's type from observing stable inflation before a liquidity trap, jeopardizing the efficiency of forward guidance policy. We derive optimal policy in a new-Keynesian model subject to liquidity traps where agents are uncertain about the central banker's type and we show that the credible central banker can signal his type by raising inflation before a trap. We show that this signaling motive can justify level of inflation well above 2% but also that the low inflation volatility during the Great Moderation was insufficient to ensure fully efficient forward guidance when needed

Mots clés : Forward Guidance, In ation, Signaling

  • ECO/SCD-2016-1155
  • What Are Analytic Narratives?
  • P. MONGIN

Départements : Economie et Sciences de la décision, GREGHEC (CNRS)

The recently born expression "analytic narratives" refers to studies that have appeared at the boundaries of history, political science, and economics. These studies purport to explain specific historical events by combining the usual narrative way of historians with the analytic tools that economists and political scientists find in rational choice theory. Game theory is prominent among these tools. The paper explains what analytic narratives are by sampling from the eponymous book Analytic Narratives by Bates, Greif, Levi, Rosenthal, and Weingast (1998) and covering one outside study by Mongin (2008). It first evaluates the explanatory performance of the new genre, using some philosophy of historical explanation and then checks its discursive consistency, using some narratology. The paper concludes that analytic narratives can usefully complement standard narratives in historical explanation, provided they specialize in the gaps that these narratives reveal and that they are discursively consistent, despite the tension that combining a formal model with a narration creates. Two expository modes, called alternation and local supplementation, emerge from the discussion as the most appropriate ones to resolve this tension

Mots clés : Analytic narratives, Rational choice theory, Game theory, Historical explanation, Text, Form of discourse, Narratology.


Départements : Economie et Sciences de la décision, GREGHEC (CNRS)

We investigate the conflict between the ex ante and ex post criteria of social welfare in a novel axiomatic framework of individual and social decisions, which distinguishes between a subjective and an objective source of uncertainty. This framework permits us to endow the individuals and society not only with ex ante and ex post preferences, as is classically done, but also with interim preferences of two kinds, and correspondingly, to introduce interim forms of the Pareto principle. After characterizing the ex ante and ex post criteria, we present a first solution to their conflict that amounts to extending the former as much possible in the direction of the latter. Then, we present a second solution, which goes in the opposite direction, and is our preferred one. This solution combines the ex post criterion with an objective interim Pareto principle, which avoids the pitfalls of the ex ante Pareto principle, and especially the problem of "spurious unanimity" discussed in the literature. Both solutions translate the assumed Pareto conditions into weighted additive utility representations, and both attribute common individual probability values only to the objective source of uncertainty.

Mots clés : Ex ante social welfare, Ex post social welfare, Objective versus subjective uncertainty, Pareto principle, Separability, Harsanyi social aggregation theorem, Spurious unanimity


Départements : Economie et Sciences de la décision

This note explores conditions that admit recursive representation for a class of dynamic mechanism design problems. We derive a tight sufficient condition, called the common state property (CSP), which ensures that temporary incentive constraints guarantee implementability, and so allows to characterize the principal's problem recursively. The condition imposes no restrictions on agent's preferences and only concerns the properties of the evolution of private information.

Mots clés : First order approach, Dynamic mechanism design


Départements : Economie et Sciences de la décision

The run up to the euro currency initiated a period of capital inflows into southern European countries, i.e., Spain, Portugal, Italy and Greece. We document that those countries, and only them among OECD countries, concomitantly experienced a decline in the quality of their institutions. We confirm the joint pattern of capital inflows and institutional decline in a large panel of countries. We show theoretically that this joint pattern naturally follows from a "soft budget constraint" syndrome wherein persistently cheap external funding undermines incentives to maintain good institutions - understood here as the degree of government commitment not to support inefficient firms. Low institutional quality ultimately raises the share of inefficient firms, which lowers average productivity and raises productivity dispersion across firms - the typical pattern of productivity in southern Europe over the period under consideration

Mots clés : TFP, Institutions, Current account


Départements : Economie et Sciences de la décision

We study the effects of financial shocks on labor markets in a model with both labor and financial frictions, two types of productive capital, physical and intangible, and in which only the former serves as collateral. A tighter borrowing constraint in this environment leads to a fall in credit and investment, skewed in detriment of intangibles, which in its turn lowers the marginal product of labor and reduces the incentives to hire workers. When feeding into the model financial shocks estimated from the data, we find that they explain labor outcomes during the last three downturns in the US, including the sharp increase in unemployment during the great recession

Mots clés : Financial Shocks, Intangible Assets, Business Cycles, Employment Volatility


Départements : Economie et Sciences de la décision, GREGHEC (CNRS)

We debate the motivation for and effectiveness of public policies to encourage individuals to become entrepreneurs. Reviewing established evidence we find that most western world policies do not greatly reduce or solve any market failures but instead waste taxpayers’ money, encourage those already intent on becoming entrepreneurs, and mostly generate one-employee businesses with low growth intentions and a lack of interest in innovating. Most policy initiatives that would have the effect of promoting valuable entrepreneurship would not be recognizable as such, because they would primarily address other market failures: a central-payer healthcare would remove health-care related distortions affecting employment choices; greater STEM education would produce more engineers of which some start valuable new firms; and labor market reform to encourage hiring immigrants in jobs they have been educated for would reduce inefficient allocation of talent to entrepreneurship.

Mots clés : entrepreneurship; public policy


Départements : Economie et Sciences de la décision, GREGHEC (CNRS)

The Intergovernmental Panel on Climate Change has developed a novel framework for assessing and communicating uncertainty in the findings published in their periodic assessment reports. But how should these uncertainty assessments inform decisions? We take a formal decision-making perspective to investigate how scientific input formulated in the IPCC's novel framework might inform decisions in a principled way through a normative decision model.


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