1. in psychotherapy, any of several variables that are common to various types of therapy, such as the therapeutic alliance, and that promote therapeutic success regardless of the different approaches used; common factors can thus be contrasted with factors that are unique to a particular therapy, such as the use of interpretation. The concept of common factors is a premise underlying integrative psychotherapy. Therapeutic factors are similar but typically apply to therapies with groups. [first articulated by Saul Rosenzweig in a 1936 article, “Some Implicit Common Factors in Diverse Methods of Psychotherapy”]

2. see specific factor.