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Jacques Drèze

Jacques Drèze is a mathematics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Jacques Drèze rather than just read about it. In short: 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.

Key takeaways

  • Jacques Drèze belongs to mathematics; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Jacques Drèze to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Jacques Drèze from memory before moving on to harder problems.

Reference excerpt

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.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Jacques Drèze

Start with the simplest possible case. Write down what Jacques Drèze claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Jacques Drèze before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Jacques Drèze ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Jacques Drèze

In research
Jacques Drèze appears in mathematics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Jacques Drèze in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Jacques Drèze is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1929 births, 2022 deaths, Academic staff of the Université catholique de Louvain, so understanding it makes those chapters shorter.
In everyday life
Look for Jacques Drèze outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Jacques Drèze in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Jacques Drèze means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Jacques Drèze out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Jacques Drèze in simple terms?

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.

Why does Jacques Drèze matter?

Because it connects several mathematics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Jacques Drèze?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Jacques Drèze.

Tags

  • 1929 births
  • 2022 deaths
  • Academic staff of the Université catholique de Louvain
  • Bayesian econometricians
  • Bayesian statisticians
  • Belgian economists
  • Belgian operations researchers
  • Belgian statisticians
  • Columbia University alumni
  • Corresponding fellows of the British Academy
  • Econometricians
  • Fellows of the American Academy of Arts and Sciences

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