Widiger, Costa, and McCrae (2002) proposed a four-step procedure for the diagnosis of a personality disorder from the perspective of the FFM. The first step is to assess the person in terms of the domains and facets of the FFM using, for instance, the NEO PI-R or the SIFFM. The second step is to determine whether the person has any impairments or problems in living associated with his or her personality traits. The second step is provided because the existing measures of the FFM do not systematically or comprehensively assess for impairments associated with each personality trait. For example, persons with elevations on NEO PI-R conscientiousness will be high in order, dutifulness, and achievement striving, but they may not possess maladaptive variants of these traits, which impede their functioning.
