ABSTRACT
In any chapter that is focused on issues of measurement, it is reasonable to begin by asking “Why should people in the intellectual disability field value efforts to measure a psychological construct such as support needs?” What is to be gained from investing time, energy, and resources into tools and/or processes that, upon completion, yield a number or a set of numbers? The answer is that assessing (i.e., collecting information) and measuring (i.e., quantification of information gathered from assessment) are a means to an end. The critical assumption on which all assessment activities are based is that the life experiences of students with intellectual disability can be improved if the decisions made by schools and planning teams are based on accurate and relevant information, and conversely, that the life experiences of students will suffer if decisions are made with incomplete or faulty information.
