Kelvin John Lancaster (10 December 1924 – 23 July 1999) was an Australian mathematical economist and John Bates Clark professor of economics at Columbia University. He is best known for the development of the Theory of the Second Best with Richard Lipsey. Lancaster was also active in developing the calculus of qualitative economics, formulating the household production function, and applying the hedonic model to the estimation of housing prices.
In a 1966 paper, Lancaster developed what he called a "new theory of consumer demand", in which the then standard microeconomic demand theory was modified by stipulating that what consumers are seeking to acquire is not goods themselves (e.g. cars or train journeys) but the characteristics they contain (e.g. transport from A to B, display of fashion sense). As Palda (2013) explains