Key Economists Behind Price Elasticity

Antoine Augustin Cournot (1801-1877)

A French mathematician whose 1838 Researches into the Mathematical Principles of the Theory of Wealth was the first serious attempt to apply calculus to economic behavior. Cournot represented demand as a continuous function of price and used it to derive a monopolist's profit-maximizing output — the foundation of what is still taught as Cournot competition. By making the price-quantity relationship a function that could be differentiated, he created the mathematical space in which elasticity could later be defined. The book sold poorly and was neglected in his lifetime; Marshall and Walras were among those who later credited him.

Alfred Marshall (1842-1924)

Marshall coined and defined elasticity of demand in Principles of Economics (1890), and the definition he gave — the proportional change in quantity relative to the proportional change in price — is the one still used. His insistence on percentage changes rather than slopes is what makes elasticity comparable across goods measured in different units. Marshall also connected elasticity to practical questions: which goods bear a tax most heavily, how a producer's revenue responds to a price cut, and why necessities and luxuries behave differently. He additionally emphasized that demand becomes more elastic as buyers are given more time to adjust.

Frank Ramsey (1903-1930)

A Cambridge mathematician and philosopher who died at 26 after producing work of extraordinary influence. His 1927 paper "A Contribution to the Theory of Taxation" asked how a government should spread a fixed revenue requirement across goods to minimize the resulting loss of economic efficiency. The answer depends on elasticity: taxing goods whose quantities respond strongly to price causes larger distortions, so, other things equal, less responsive goods should bear relatively higher rates. The result underlies Ramsey pricing in regulated industries and remains a reference point in public finance, alongside serious debates about its fairness implications.

Joan Robinson (1903-1983)

A Cambridge economist whose The Economics of Imperfect Competition (1933) developed the analysis of firms that face downward-sloping demand curves rather than a single market price. Her work made explicit how a firm's marginal revenue depends on the elasticity of the demand it faces, and it provided the standard framework for analyzing price discrimination — charging different prices to buyer groups with different elasticities. Robinson is also credited with popularizing the term monopsony for a market with a dominant buyer. Her framework is why elasticity is inseparable from any modern discussion of pricing power.

Henry Schultz (1893-1938)

An American economist and pioneer of econometrics whose The Theory and Measurement of Demand (1938) was among the first large-scale efforts to estimate real demand curves and elasticities from statistical data, mainly for agricultural products. Schultz confronted head-on the problem that observed prices and quantities are generated by supply and demand shifting together, which means a naive correlation does not recover either curve. That identification problem became one of the central methodological questions of twentieth-century empirical economics, and the techniques developed to solve it are why credible elasticity estimates exist today.