## Quick Reference

A utility function that can be subjected to a positive affine transformation without altering the implied preference order. A positive affine transformation applied to the initial utility function *U* generates the transformed utility function *U* = a + bU,* where *b* > 0. The utility function *U* is cardinal if the functions *U* and *U** represent the same set of underlying preferences. An example of cardinal utility is an expected utility function. See also interpersonal comparisons; ordinal utility.

*Subjects:*
Economics.