Measurement pervades almost every facet of our lives and daily activities. We measure a great variety of things (e.g., weight, temperature, ingredients to be used in cooking, time, distance). At one time or another, we are measured by various people (e.g., physicians, teachers, supervisors, college admission officers, psychologists) on a wide range of things (e.g., blood pressure, achievement, productivity, aptitudes, attitudes, anxiety). In short, much of what we do, decisions we make, and decisions made about us involve measurement of one kind or another.