"Ipsative" scales are any set of variables that sum to a constant for each case (e.g., the numbers of hours per day out of 24 each person devotes to work, domestic chores, leisure, eating, and sleeping). During the early days of psychometric testing and scale construction, ipsative scales were developed for measuring many psychological constructs, e.g., personality, organizational culture, performance evaluation, attitudes, values, and preferences. They were said to produce greater differentiation and to control for acquiescence responding, halo effects, impression management, and social desirability biases better than rating scales. However, by the late 20th century they had fallen out of favour, mainly because researchers didn't know how to analyse them. It turns out that straightforward methods for analysing them were developed in other disciplines. In this seminar I provide an introduction to this type of measurement, methods for analysing its data, and applications to real data-sets.