Psychometrics is the scientific study of psychological measurement, the goal of which is to validly measure differences between individuals and groups in psychosocial qualities such as attitudes and personality. There are two aspects:

  1. Developing and testing tools to validly measure psychological qualities (such as knowledge, attitudes and opinions, emotions, cognitions, personality, and so on).
  2. Developing a science (theory, methods, and findings) of and about the measurement of psychological qualities.
Flowers are like fuzzy concepts - each varies, yet each has a distinct pattern.

See also