Psychometrics includes educational testing, measurement of attitudes and perceptions, personality testing, opinion surveys, health inventories, and other forms of psychological measurement. Psychometric techniques created for measuring the human mind have also proven useful in biometrics and other fields that deal with measuring the intangible. This article is a comprehensive summary of the techniques for psychometric analysis including reliability, generalizability, and validity assessments. The article also presents the evolution of psychometric theory, popular measurement models, and a snapshot of new directions in the field.