Belgian economist (1929–2022)
Jacques H. Drèze (5 August 1929 – 25 September 2022) was a Belgian economist noted for his contributions to economic theory, econometrics, and economic policy as well as for his leadership in the economics profession. Drèze was the first President of the European Economic Association in 1986 and was the President of the Econometric Society in 1970.
Jacques Drèze was also the father of five sons. One son is the economist, Jean Drèze, who is known for his work on poverty and hunger in India (some of which has been in collaboration with Amartya K. Sen); another son, Xavier Drèze, was a professor of Marketing at UCLA.
Contributions to economics.
Drèze's contributions to economics combine policy relevance and mathematical techniques.
Indeed, models basically play the same role in economics as in fashion: they provide an articulated frame on which to show off your material to advantage ... ; a useful role, but fraught with the dangers that the designer may get carried away by his personal inclination for the model, while the customers may forget that the model is more streamlined than reality.
Economics of uncertainty and insurance.
Between games of strategy and games against nature, there remains a middle ground where uncertainties are partially controllable by the decision-maker—situations labelled "games of strength and skill" by von Neumann and Morgenstern, or "moral hazard" in subsequent work. Such problems of moral hazard have been discussed by Jacques Drèze in his dissertation, leading to the 1961 paper (8), whose analysis was generalized in 1987 (76), and simplified in 2004 (123). Drèze's theory allows for preferences depending on the state of the environment. Rational behaviour is again characterised by subjective expected utility maximisation, where the utility is state-dependent, and the maximisation encompasses the choice of an optimal subjective probability from an underlying feasible set.
With reference to state-dependent preferences and moral hazard, a natural application of long-standing interest to economists concerns the provision of safety, for instance through road investments that are aimed at saving lives. In this area, Jacques Drèze introduced in 1962 (12) the "willingness-to-pay" approach, which is now widely adopted. That approach rests on individual preferences aggregated as per the theory of public goods. The willingness to pay approach thus fits squarely in economic theory.
The work of Jacques Drèze on the economics of uncertainty through the mid-eighties is collected in his volume "Essays on Economic Decisions under Uncertainty" (B2), published in 1987.
The book is organised in seven parts, covering successively decision theory, market allocation, consumption, production, the firm under incomplete markets, labor and public decisions. Under market allocation comes an important paper (21) on the interpretation and properties of the general equilibrium model pioneered in Arrow (1953). The more significant piece in the next part is a classic paper with Franco Modigliani on savings and portfolio choice under uncertainty (28). There follow three papers on industry equilibrium (17, 42, 62).
In 1975 Drèze contributed "the first general equilibrium analysis of quantity rationing necessitated by prices failing to adjust to equate supply and demand", which "have introduced significant elements of realism to the basic model, . . . given insight, and . . . have had a major impact on subsequent work. For example, the fix-price approach to Keynesian macroeconomics . . . grows largely out of the Drèze paper."
In the early seventies, motivated by the potential role of price rigidities for enhancing risk-sharing efficiency, Jacques Drèze undertook to define equilibria with price rigidities and quantity constraints and to study their properties in a general equilibrium context. His 1975 paper (36, circulated in 1971) introduces the so-called "Drèze equilibrium" at which supply (resp. demand) is constrained only when prices are downward (resp. upward) rigid, whereas a preselected commodity (e.g. money) is never rationed. Existence is proved for arbitrary bounds on prices, through an original approach repeatedly used ever since. That paper is a widely cited classic. It was followed by several others (51, 55, 63, 75), exploring the properties of the new concept. Of particular significance to future developments is a joint paper with Pierre Dehez (55), which establishes the existence of Drèze equilibria with no rationing of the demand side. These are called "supply-constrained equilibria". They correspond to the empirically relevant macroeconomic situations.
Macroeconomic consequences of microeconomics.
In the meantime, Jean-Pascal Bénassy (1975) and Yves Younès (1975) had approached the same problem from a macroeconomic angle, for the more restrictive case of fixed prices. There developed a lively interest in fixed price economies, and specifically in a three-good macroeconomic model, first formulated by Robert Barro and Herschel Grossman (1971) and then studied extensively by Edmond Malinvaud (1977). That model invited empirical estimation. The new statistical challenges posed by "disequilibrium econometrics" were attacked at CORE by two students of Jacques Drèze, namely Henri Sneessens (1981) and Jean-Paul Lambert (1988). Following a joint paper by Drèze and Sneessens (71), a major project (the European Unemployment Program) directed by Jacques Drèze and Richard Layard led to the estimation of a common disequilibrium model in ten countries (B4, 93, 94). The results of that successful effort were to inspire policy recommendations in Europe for several years.
The next steps in the theoretical research came with the work of John Roberts on supply-constrained equilibria at competitive prices, and then with the dissertation of Jean-Jacques Herings at Tilburg (1987, 1996). In both cases, there appear results on the existence of a continuum of Drèze equilibria.
Following the work of Roberts and Herings, Drèze (113) proved the existence of equilibria with arbitrarily severe rationing of supply. Next, in a joint paper with Herings and others (132), Drèze established the generic existence of a continuum of Pareto-ranked supply-constrained equilibria for a standard economy with some fixed prices.
An intuitive explanation of that surprising result is this: if some prices are fixed and the remaining are flexible, the level of the latter prices relative to the former introduces a degree of freedom that accounts for the multiplicity of equilibria; globally, less rationing is associated with a higher price level; the multiplicity of equilibria thus formalises a trade-off between inflation and unemployment, comparable to a Phillips curve. In this analysis, the continuum is interpreted as reflecting coordination failures, not short-run price dynamics à la Phillips. The fact that price-wage rigidities can sustain coordination failures adds a new twist to explanations of involuntary unemployment. At the same time, multiple equilibria create problems for the definition of expectations, and introduce a new dimension of uncertainty.
Starting with a paper in "Econometrica" by Dierker, Guesnerie and Neuefeind (1985), a theory of general equilibrium has developed for economies with non-convex production sets, where firms follow well-defined pricing rules. In particular, the existence theorems of increasing generality cover (to some extent, because of various differences in assumptions) the case of Ramsey-Boiteux pricing. Those interested primarily in applications might express skepticism, perhaps even horrified skepticism, upon realizing that 90 pages of a serious economics journal—a 1988 issue of "The Journal of Mathematical Economics"---were devoted to existence proofs of equilibrium in non-convex economies, under alternative formulations of the assumption that marginal cost pricing entails bounded losses at normalized prices. Still, I think that economic research must cover the whole spectrum from concrete applications to that level of abstraction.
Theory of the firm.
Drèze gave a public lecture on "Human Capital and Risk Bearing" (48). The innovative idea here is the transposition of the reasoning underlying the theory of "implicit labour contracts" to the understanding of wage rigidities and unemployment benefits. When markets are incomplete, so that workers cannot insure the risks associated with their future terms of employment, competitive clearing of spot labour markets is not the second-best efficient: wage rigidities cum unemployment benefits offer scope for improvement.
The lecture develops this theme informally. The conclusion, stated with specific reference to labour markets, has more general validity. It applies to any situation where the uninsurable uncertainty about future prices results in welfare costs. Even though price rigidities entail a loss of productive efficiency, this can be more than offset by a gain of efficiency in risk-sharing. What may be specific to the labour market is the realistic possibility of controlling (minimum) wages and organising unemployment compensation. The analysis implies that the claim that wage flexibility is efficient requires qualification.
For "price-wage rigidities", the presence of rigidities receives an explanation in Section Seven of Drèze's lecture: Under incomplete markets, wage rigidities contribute to risk-sharing efficiency. The theme of the 1979 lecture (48) is taken up in several papers (91, 95, 101), exploring the definition and implementation of second-best wage rigidities.
Since then, Jacques Drèze has examined ways of reconciling flexibility of labour costs to firms with risk-sharing efficiency of labour incomes, if needed through wage subsidies (119, 125, 131).
Disequilibrium.
Drèze has suggested that research needs both to search for "microeconomic foundations for macroeconomics" and to consider the "macroeconomic consequences of microeconomics", and Drèze had contributed to the latter project of macroeconomic consequences of microeconomics.
In the early seventies, motivated by the potential role of price rigidities for enhancing risk-sharing efficiency, Jacques Drèze undertook to define equilibria with price rigidities and quantity constraints and to study their properties in a general equilibrium context. His 1975 paper (36, circulated in 1971) introduces the so-called "Drèze equilibrium" at which supply (resp. demand) is constrained only when prices are downward (resp. upward) rigid, whereas a preselected commodity (e.g. money) is never rationed. Existence is proved for arbitrary bounds on prices, through an original approach repeatedly used ever since. That paper is a widely cited classic. It was followed by several others (51, 55, 63, 75), exploring the properties of the new concept. Of particular significance to future developments is a joint paper with Pierre Dehez (55), which establishes the existence of Drèze equilibria with no rationing of the demand side. These are called "supply-constrained equilibria". They correspond to the empirically relevant macroeconomic situations.
In the meantime, Jean-Pascal Bénassy (1975) and Yves Younès (1975) had approached the same problem from a macroeconomic angle, for the more restrictive case of fixed prices. There developed a lively interest in fixed price economies, and specifically in a three-good macroeconomic model, first formulated by Robert Barro and Herschel Grossman (1971) and then studied extensively by Edmond Malinvaud (1977). That model invited empirical estimation. The new statistical challenges posed by "disequilibrium econometrics" were attacked at CORE by two students of Jacques Drèze, namely Henri Sneessens (1981) and Jean-Paul Lambert (1988). Following a joint paper by Drèze and Sneessens (71), a major project (the European Unemployment Program) directed by Jacques Drèze and Richard Layard led to the estimation of a common disequilibrium model in ten countries (B4, 93, 94). The results of that successful effort were to inspire policy recommendations in Europe for several years.
The next steps in the theoretical research came with the work of John Roberts on supply-constrained equilibria at competitive prices, and then with the dissertation of Jean-Jacques Herings at Tilburg (1987, 1996). In both cases, there appear results on the existence of a continuum of Drèze equilibria. Following these leads, Drèze (113) proved the existence of equilibria with arbitrarily severe rationing of supply. Next, in a joint paper with Herings and others (132), the generic existence of a continuum of Pareto-ranked supply-constrained equilibria was established for a standard economy with some fixed prices. An intuitive explanation of that surprising result is this: if some prices are fixed and the remaining are flexible, the level of the latter prices relative to the former introduces a degree of freedom that accounts for the multiplicity of equilibria; globally, less rationing is associated with a higher price level; the multiplicity of equilibria thus formalises a trade-off between inflation and unemployment, comparable to a Phillips curve.
Econometrics and the European Unemployment Programme.
Two young French economists, Jean-Pascal Bénassy (1975) and Yves Younès (1975), approached the same problem from a macroeconomic angle, for the more restrictive case of fixed prices. There developed a lively interest in fixed-price economies, and specifically in a three-good macroeconomic model, first formulated by Robert Barro and Herschel Grossman (1971) and then studied extensively by Edmond Malinvaud (1977).
That model invited empirical estimation. The new statistical challenges posed by "disequilibrium econometrics" were attacked at CORE by two students of Jacques Drèze, namely Henri Sneessens (1981) and Jean-Paul Lambert (1988), whose dissertations were published and widely read. Drèze and Sneessens proposed and estimated a disequilibrium model of Belgium's open economy (71). This model became the prototypical model estimated by