Trait theory is based on observed behaviors. There are many personality traits that are linked with other traits. A person who is very ordered and neat, for example, will usually be responsible and a strong believer in rules. When a cluster of traits is repeatedly found in people, psychologists refer to the cluster as a personality type. By classifying individuals into personality types, it becomes easier to describe, understand and predict their behavior.
Temperament theory is another method of classifying personality types.
Instead of classifying people by observed behaviors, it groups them according to their core needs or desires. Behavior can then be determined or predicted because a person's behavior will reflect what that person really wants or needs. In addition to helping understand and predict behavior, temperament theory models are also useful because they provide a key to understanding the sources of self-esteem of the different types. Some personality typing instruments are based on trait theory and some are based on temperament theory. It turns out that there is a strong correlation between type divisions no matter which method is used.