<P> Suppose a certain agent has a preference ordering over random outcomes (lotteries). If the agent can be queried about his preferences, it is possible to construct a cardinal utility function that represents these preferences . This is the core of the Von Neumann--Morgenstern utility theorem . </P> <P> Among welfare economists of the utilitarist school it has been the general tendency to take satisfaction (in some cases, pleasure) as the unit of welfare . If the function of welfare economics is to contribute data which will serve the social philosopher or the statesman in the making of welfare judgements, this tendency leads perhaps, to a hedonistic ethics . </P> <P> Under this framework, actions (including production of goods and provision of services) are judged by their contributions to the subjective wealth of people . In other words, it provides a way of judging the "greatest good to the greatest number of persons". An act that reduces one person's utility by 75 utils while increasing two others' by 50 utils each has increased overall utility by 25 utils and is thus a positive contribution; one that costs the first person 125 utils while giving the same 50 each to two other people has resulted in a net loss of 25 utils . </P> <P> If a class of utility functions is cardinal, intrapersonal comparisons of utility differences are allowed . If, in addition, some comparisons of utility are meaningful interpersonally, the linear transformations used to produce the class of utility functions must be restricted across people . An example is cardinal unit comparability . In that information environment, admissible transformations are increasing affine functions and, in addition, the scaling factor must be the same for everyone . This information assumption allows for interpersonal comparisons of utility differences, but utility levels cannot be compared interpersonally because the intercept of the affine transformations may differ across people . </P>

The word util has been used by economists