Personality Assessment

Personality assessment, in its broadest sense, includes any technique that is used to describe or make inferences about the characteristic traits, attitudes, beliefs, values, needs, motives, emotional states, coping styles, or aspirations of an individual. Personality assessment can take many forms, including an Internet dating questionnaire, an epitaph, a letter of recommendation, a psychodiagnosis, an integrity test administered as part of an employment application, and a psychobiography based on a historical record.

For the present purposes, however, three major functions of personality assessment will be considered: assessment in the service of basic research and theory explication; assessment in applied psychology, including therapeutic, organizational, and forensic settings; and assessment in self-exploration. These different functions of personality assessment determine the personality characteristics to be measured and the instrument or method to be used.

What to Measure: The Content of Personality Assessment

Personality characteristics constitute a fuzzy set, populated by constructs as diverse as extraversion, physical attractiveness, creativity, sexual orientation, gender, and psychopathology. Yet there is some consensus, for at its core, personality is now generally conceptualized at three strata or levels of analysis. In parallel with these three levels of analysis, three goals of personality assessment can be described. The most ambitious of these is understanding, followed by explanation, then description and prediction.

Narrative Accounts

The deepest of the three strata is the life story, a set of meanings that unfolds over time and which can be linked into a narrative account. The outstanding characteristic of the life story is its individuality. Assessment at this level is aimed at an abstract understanding of the person, and typically occurs in specialized contexts such as case studies, biographies, and epitaphs. The narrative account can serve as an implicit criterion against which respondents evaluate the validity of more shallow and more quantitative assessments of personality.

Characteristic Adaptations

Characteristic adaptations represent a heterogeneous middle level of analysis. These include motives and related mechanisms such as coping and defensive styles, and cognitive factors such as schemas, plans, generalized expectancies, and beliefs. Characteristic adaptations also include developmental constructs such as stage of personality development. A prominent measure at this level is the Washington University Sentence Completion Test, a measure of ego development. Given the heterogeneity of this level, assessment of characteristic adaptations serves many functions. For heuristic purposes, however, the primary reason for assessing characteristic adaptations is to achieve an explanation of why behavior does or does not occur.


The most accessible and easily quantified level of personality is that of the trait or disposition. The primary objective when assessing personality traits or dispositions is the description and prediction of behavior.

The Meaning of Traits

Traits, the primary unit of personality description, are relatively enduring ways in which individuals differ. Assessment at the level of traits is variable centered and nomothetic, focusing on differences among individuals, as opposed to the person-centered and idiographic approach that focuses on individuals, and that typically characterizes assessment at deeper and more abstract levels of personality.

Because people differ in many ways, psychologists must decide which differences are worthy of study. While evolutionary, psychoanalytic, and behavioral perspectives have been influential in suggesting traits that are worthy of attention when assessing personality, a more pragmatic, data-driven approach has generally held sway. At the most basic level, trait attributions are made based upon simple summaries of past behavior, and because what has happened in the past is likely to recur, traits can serve as valid predictors of future behaviors. Beyond this summary approach, if one takes into account characteristics of the situation as well, traits can help explain behavior and contribute to an understanding of the person. For example, an observation that “Jane has panic attacks in crowds” might lead to an inference of the form that “Jane will not go to the party because she is agoraphobic.” Trait attributions can and frequently do go beyond the trivial and tautological.

The Five-Factor Model

Factor analytic results indicate that many of the 18,000 words used to describe personality in the English language represent variations of five basic traits. The five-factor model (FFM) and its variants provide the most important contemporary perspective on traits, effectively serving as a paradigm for contemporary research in personality assessment. The five factors, sometimes referred to as the Big Five, are generally conceived of as extraversion, neuroticism, conscientiousness, agreeableness, and openness to experience.

Extroversion. The breadth of the five factors can leave them open to multiple interpretations, and this is particularly true for extraversion. For Jung, extraversion and intraversion describe an individual’s preferred direction of attention or focus: Extraverts focus on the external, shared world, while introverts focus on internal, idiosyncratic experiences. Eysenck offered a physiological explanation of extraversion (which he labels extroversion) based on the level of arousal of the reticular activating system. Eysenck viewed extraverts as endogenously understimulated (and so desirous of external stimulation and excitement), and introverts as overstimulated and consequently likely to seek quieter settings. An affective conception is that extraverts are more likely than introverts to experience and report positive affect. From a behavioral perspective, the most visible component of extraversion is social motivation and social skill. The combination of social interest and positive affect has given rise to the interpretation of extraversion as surgency or lively sociability.

Given the breadth of the extraversion-introversion dimension of personality, it is difficult to imagine conditions under which the dimension would not be relevant in understanding individual differences in the motivations, behaviors, and satisfactions experienced by individuals. Extraversion is measured in most comprehensive personality inventories used by psychologists.

Neuroticism. Neuroticism represents a tendency to experience negative affect, anxiety, and emotional upset; its opposite may be understood as well-being, emotional stability, or adjustment. Neuroticism is associated with sensitivity to punishment rather than reward, and with behavioral inhibition rather than activation. The Americans with Disabilities Act may proscribe the explicit measurement of neuroticism in applied settings (i.e., selection) because psychological health is conceptualized as a component of physical health.

Conscientiousness. Conscientiousness is a broad factor that includes discipline, a respectful attitude towards rules, work ethic, behavioral constraint, organization, responsibility, socialization, and impulse control. Conscientiousness is the Big Five trait most closely linked with job performance, and it is associated with scores on the integrity tests that are widely used in personnel selection. The relationship between conscientiousness and social conformity has led to some confusion, for the term conscientiousness also denotes a stage in personality development characterized by the transcendence of mindless conformity and the internalization of a moral code.

Agreeableness. Agreeableness includes attributes such as likability, friendly compliance, warmth, and conformity, as well as communion, the positive core of the feminine gender role. Agreeableness is the most evaluative laden of the five factors. Because agreeableness is related to likability, observer ratings of agreeableness are more subjective and may show less interrater consensus than observer ratings of other traits.

Openness. The core of Openness to Experience includes breadth of interests, curiosity, and cultural sophistication. For some authors, this factor includes characteristics as diverse as flexibility, intelligence, political liberalism, and hypnotic susceptibility. There is both less cross-cultural generalizability and less agreement on the specific content for this factor. Openness generally appears as the smallest of the factors in statistical analyses. Nonetheless, both the core of openness and its more peripheral, less consensual components are empirically important in many settings.

Beyond the Five Factors

The five-factor model is one useful starting point for personality assessment, but additional personality characteristics have been identified that may be conceptualized as lying between, beyond, and beneath the five factors. The five factors may be thought of as geometric axes between which other sets of axes may constitute a richer or more theoretically sound framework. For example, Extraversion and Neuroticism may be rotated to the arguably more elemental concepts of Anxiety and Impulsivity. Similarly, beyond the five factors, additional traits appear to be poorly represented in the five factor space, including spirituality, attractiveness, insight, ambition, unpleasantness, manipulativeness, egotism, seductiveness, integrity, thriftiness, risk taking, and humor. Beneath the five factors lie narrower constructs that may have more predictive utility. Punctuality, in some circumstances, may be more informative than the broader trait of Conscientiousness by which it is imperfectly subsumed.

The five-factor model derives ultimately from lay usage; the factor analytic methods that underpin the model provide, in principle, a nonredundant and potentially comprehensive set of tools for describing the universe of personality trait terms. However, lay usage is not the only useful source from which to derive personality characteristics, and statistical elegance is not the only meaningful criterion governing the selection of a variables. For these reasons, many psychologists continue to prefer other sets of constructs, including those based on the theoretical positions outlined by Jung, Murray, Eysenck, and Gough. These positions are considered in the next section.

How to Measure: The Tools of Personality Assessment

The most widely used methods of assessing personality include self-report measures and observer rating scales. Self-report measures, in turn, include multitrait personality inventories, single-trait personality scales, and projective techniques.

Personality Inventories

Personality inventories are questionnaires that provide scores on a number of traits or characteristics. These measures typically take 30 to 75 minutes to complete and are intended for administration to adults. Most inventories consist primarily of statements (e.g., “I would be uncomfortable in a foreign city”) or adjectives (e.g., “friendly”). Respondents are instructed to answer using a dichotomous format (e.g., true/false) or a 3-to-7-point (e.g., agree strongly, agree, neither agree nor disagree, disagree, or disagree strongly) format.

The NEO Personality Inventory, Revised

The NEO Personality Inventory, Revised (NEO PI-R) is the best-known and most empirically supported measure of the five factors. The NEO PI-R can be administered in a third-person form for generating observer ratings as well as the more familiar first-person form. In addition to measures of the five factors, the NEO PI-R also provides measures of 30 lower-level facet scales, such as Gregariousness (a facet of Extraversion), Trust (Agreeableness), and Aesthetics (Openness). A short form of the instrument, the NEO Five-Factor Inventory (NEO-FFI), provides scores only at the level of the five broad domains. In addition, a second abbreviated test, the NEO-4, is available for applications in which the measurement of Neuroticism is inappropriate. The NEO PI-R is an expansion of two earlier tests, the NEO (which did not include measures of Agreeableness or Conscientiousness), and the NEO PI (which included facet scales for only the first three domains).

The NEO PI-R has been translated into some 25 languages, and it has been used extensively in studies ranging from descriptions of American presidents to cross-sectional studies of personality development. With respect to the latter, the five factors generally appear quite stable throughout adulthood. In vocational assessment, several studies indicate that the NEO PI-R complements, but does not replace, measures of vocational interest. Scores on the NEO PI-R Neuroticism scale have been shown to decrease during therapy, while Conscientiousness scores have increased during the course of a drug rehabilitation program. NEO PI-R domain scores also appear to be related to the psychologist’s assessments of treatment appropriateness and efficacy. Clients who score high on Openness are rated as benefiting from client-centered techniques, while those who score high on Neuroticism have been found to benefit from journaling and vocational techniques.

Unlike many other personality inventories, the NEO PI-R does not include indices of faking or invalidity beyond a few questions at the end of the test that directly ask if the respondent has answered honestly, accurately, and in the correct order. The rationale behind excluding validity scales includes empirical evidence that when protocols that are identified as “invalid” are excluded, test validity may be reduced rather than increased, suggesting that “invalid” protocols do, in fact, contain information. Individuals differ in the probability that they will respond in a less than honest fashion, and these individual differences may be meaningful.

Other Measures of the Five Factors

The five factors can be measured in a number of ways in addition to the NEO PI-R. Explicit measures of the five factors include the Hogan Personality Inventory (HPI), which is widely used in organizational settings, and two measures based on simple adjectives, the Goldberg Big Five Markers and the Interpersonal Adjective Scales-Revised. Additional measures of some or all of the characteristics are available that are not directly derived from the five-factor model. For example, Conscientiousness can be measured by the Rule-consciousness and Perfectionism scales of the Sixteen Personality Factor Questionnaire (16 PF), the Organization and Responsibility scales of the Jackson Personality Inventory (JPI), the Control and Harm-avoidance scales of the Multidimensional Personality Questionnaire (MPQ), and scales including Responsibility and Achievement via Conformance on the California Psychological Inventory (CPI). However, the different measures of the five factors should not be considered interchangeable. For example, the externalizing dimension of the CPI—a form of Extraversion—is largely a measure of social skills rather than social interest. High scores on Agreeableness on the NEO appear to reflect more obsequiousness and less charm than high agreeableness scores on the HPI.

The Sixteen Personality Factor Questionnaire

As with the measures of the five-factor model, the Sixteen Personality Factor Questionnaire (16 PF) was derived from factor analyses of traits selected from analyses of words appearing in the English language that describe personality. This measure, originally developed by Raymond B. Cattell in 1949 and presently in its fifth edition, now labels its measures using familiar terms (e.g., Warmth and Social Boldness) rather than the neologisms (e.g., Schizothymia and Threctia) that were used in earlier editions. The measure incorporates a multilevel approach to assessment; scores are provided on both medium-bandwidth primary dimensions and the five global factors of Extraversion, Anxiety, Tough Mindedness, Independence, and Self-Control. The 16 PF continues to include items that measure reasoning skills or intelligence as well as core characteristics of personality. This confounding of distinct constructs such as cognitive ability and personality in the scores obtained from the 16 PF is regarded as an undesirable feature by some psychologists.

The Eysenck Inventories and Related Measures

A number of measures are based on models of personality that derive from a concern for both psychometric and biological parsimony. The most prominent of these is the family of measures derived by Hans Eysenck. The Eysenck Personality Questionnaire Revised (EPQR) is a 100-item instrument that measures the three broad factors of Extraversion, Neuroticism, and Psychoticism. The label for the last of these is at best idiosyncratic, as high scorers on the measure are much more likely to be impulsive than to suffer from serious psychopathology. In addition to the three main factors, the EPQR includes a Lie scale that measures conformity, the desire to create a favorable impression, and the potentially invalidating tendency to “fake good.” A 48-item short form, the EPQRS, is also available.

The Zuckerman-Kuhlman Personality Questionnaire (ZKPQ) is similar in length to the EPQ-R, and measures five alternative factors: Impulsive Sensation Seeking, Neuroticism-Anxiety, Aggression-Hostility, Activity, and Sociability. It also includes a validity scale titled Infrequency. Impulsive Sensation Seeking has been found to be associated with a variety of risk-taking behaviors.

Cloninger’s Temperament and Character Inventory (TCI) includes 240 items measuring four biologically based parameters (i.e., Novelty Seeking, Harm Avoidance, Reward Dependence, and Persistence) and three dimensions of character (i.e., Self-Directedness, Cooperativeness, and Self-Transcendence). The TCI is used primarily in psychiatry and medicine.

The California Psychological Inventory

The California Psychological Inventory (CPI) is presently available in a 434-item version and an abbreviated 260-item form. Twenty-nine scales are included on both of these forms; all but two of the corresponding scales correlate .89 or higher.

The core constructs measured by the CPI are “folk concepts” whose relevance is demonstrated by their use in a variety of societies or cultures. Measures of these scales, alone and also in combination, are designed to predict how others will see the respondent and how the respondent will behave in consequential situations. Folk concept scales include measures of interpersonal orientation or social tendencies (such as Dominance and Sociability) and orientation toward rules and norms (such as Responsibility and Self-Control). These themes are also assessed in two broader “vector” scales, which conjointly form a fourfold typology. Alphas are extraverted, Betas are introverted, and both resonate to rules. Gammas and Deltas, extraverts and introverts, respectively, are skeptical of rules and resistant of the status quo. A third vector assesses degree of realization (i.e., the extent to which the potential embodied in a type is met).

Taken together, the vector scales form a structural model based on the premise that each of the four types may contribute constructively to society, or struggle uniquely. Alphas may be benevolent leaders at high levels of realization, but at lower levels of realization they may appear tyrannical and authoritarian. Betas may appear to be saintly at higher levels of realization or constricted conformists at lower levels. At higher and lower levels, respectively, Gammas may be voices for progressive change or histrionic whiners, and Deltas may be visionary or suffer internal conflicts that lead to psychosis.

The typology is empirically useful in predicting meaningful life events. For example, among high school students, the typology is related to the likelihood of attending college. The rate of college matriculation is greatest for Alphas and lowest for Deltas. Similarly, there is a disproportionate representation of Alphas and Gammas among students enrolled in graduate programs in counseling psychology. While these findings are informative, the limitations of typologies discussed below in the section on measures based on Jung’s model must be kept in mind.

In addition to the two central themes and the typology, the CPI also includes folk scales that assess academic and cognitive functioning (e.g., Achievement via Conformance and Achievement via Independence) and personal style (e.g., Flexibility and Psychological Mindedness or Insightfulness). The CPI also provides a number of scales that assess constructs such as Law Enforcement Orientation (LEO), Work Orientation, Managerial Potential, Leadership, and Creative Temperament. Many of these scales were empirically developed, using criterion groups or correlations with behavioral criteria.

The length of the CPI, even of the shorter version, may appear to be daunting, but the potential for tedium is moderated by the true/false response format and the use of engaging item content. For example, the Communality scale, which exists in part to assess random or improbable responding, includes items that are intended to be egosyntonic (e.g., “I would fight if someone tried to take my rights away” and “Education is more important than most people think”). The CPI is useful as a clinical tool for revealing the strengths of a client, as well as for predicting performance in a range of settings, from health care to corrections, and from academic to organizational.

Measures Based on Murray’s Model

Probably the most fertile theoretical basis for personality tests is Henry Murray’s theory of needs.

Douglas N. Jackson’s Personality Research Form (PRF Form E), the most prominent self-report needs assessment inventory, includes 352 items that assess 20 needs (e.g., Achievement, Affiliation, and Play). A substantial body of research attests to its validity for a variety of functions, including personnel selection and the assessment of leadership style. A second measure of needs, now largely of historical interest, is the Edwards Personal Preference Schedule (EPPS). The EPPS was unusual in its attempt to control for socially desirable or acquiescent test-taking styles by relying on a forced-choice response format. Ultimately, the elimination of variance attributable to response style reduced the validity of the instrument and it has fallen into relative disuse. Finally, the Adjective Check List consists of 300 adjectives that the respondent checks or leaves blank. Responses are scored to yield measures of 15 needs (e.g., Dominance, Exhibition, and Aggression).

Measures Based on Jung’s Model

Based on Carl Jung’s theory of psychological types, the Myers-Briggs Type Indicator (MBTI) is among the most widely administered measures of personality. All three forms of the MBTI currently in use (the 126-item Form G, the 93-item Form M, and the 144-item Form Q) provide measures of Extraversion-Introversion (E-I), Sensing-Intuition (S-N), Thinking-Feeling (T-F), and Judging-Perceiving (J-P). These four dimensions are each treated dichotomously in interpreting the MBTI, and are combined to yield 16 types. This accounts in large part for the popularity of the measure. For example, describing a person as an ENFP—an Extraverted, iNtuitive, Feeling, Perceiving type—provides a potentially parsimonious and cognitively economical description, and also offers the person an identity-buttressing membership into an imagined community of like-minded people.

Typologies are compelling, and it is likely that the changes that have been seen in other tests, notably the structural model grafted on to the CPI, have occurred in part because of the success and popularity of the MBTI. Unfortunately, there are costs associated with the reduction of scores to simple dichotomies. In particular, the reduction of important dimensions of personality to dichotomies oversimplifies the rich diversity of personality that exists among individuals. Furthermore, most individuals will score near the mean on at least one of the four dimensions of the test. As a consequence, the type classification of most individuals is likely to change if the individuals are tested at another time. These shortcomings seriously reduce the value—but not necessarily the popularity—of this approach to assessment.

The newest form in the MBTI family, form Q, provides measures of narrow facets (subscales) as well as a typological classification based on the four broad dichotomies. For Extraversion-Introversion, the core facet is Initiating-Receiving; for Judging-Perceiving, the core facet is Systematic-Casual.

While research indicates that the narrow facets provide additional information over and above what is provided by the broader measures, there is, as yet, little evidence regarding their specific content. The heart of the MBTI remains its typology, the popularity of which has led to a number of competing, and superficially similar, measures of Jungian type. These include the Grey-Wheelwright Jungian Type Survey, the Singer-Loomis Type Development Inventory, the Keirsey Temperament Sorter, and the Personal Preferences Self-Description Questionnaire.

Measures Intended for the Measurement of Psychopathology

The 338-item revised Minnesota Multiphasic Personality Inventory (MMPI-RF), scheduled for publication in late 2007, includes a set of Restructured Clinical (RC) scales that have been developed rationally on the basis of psychometric structure. The RC scales are shorter than the original clinical scales. More important, they are intended to separate the ubiquitous factor of generalized anxiety or “demoralization” from other, narrower concerns assessed in the instrument such as somaticization (i.e., a form of mental illness in which an individual manifests a psychiatric condition in the form of a physical complaint). This offers the potential for the RC scales to be less redundant and more informative than the original scales.

Another important feature of the MMPI-RF is its multilevel approach to the assessment of dysfunction. At the broadest level, three measures are included: Emotional/Internalizing (assessing emotional and mood disorders), Thought (assessing irrational cognitive processes), and Behavioral/Externalizing (assessing problems associated with under socialization or acting out). Beneath this, Somatic scales and Interest scales assess narrower problems such as Head Pain Complaints and Aesthetic-Literary interests, respectively. In addition, the MMPI-RF includes measures of dimensions of personality disorder, including Aggressiveness and Introversion. Empirical research is needed to determine whether the Restructured Clinical scales offer an improvement over the prior measure.

Single-Trait Personality Scales

In addition to the comprehensive inventories considered above, personality assessment via self-report frequently is based on responses to personality scales that assess single traits. Examples include the Beck Depression Inventory, the Locus of Control scale (and related narrower measures, such as the Health Locus of Control scale), and instruments that assess psych-ache (i.e., unbearable psychological pain associated with suicidality), alexithymia (i.e., the inability to describe emotions), adult attachment, body image, attitudes toward eating, and various social, cultural, and political attitudes.

Projective Measures: Sentence Completion Tests

Projective techniques may be seen as a combination of behavioral assessment (what a person does), self-report (what a person says), and the judgment of an observer. This article mentions only sentence completion forms, a type of projective test that appears particularly important in personality assessment. Sentence completion forms are semistructured measures in which respondents are asked to complete stems such as “My mother…” The best validated of these is Loevinger’s Washington University Sentence Completion Test, a measure of social and cognitive maturity that has been widely used in studies of personality development, particularly in the college years. A second sentence completion measure is the Rotter Incomplete Sentences Blank, which assesses emotional adjustment.

Measures for Observer Ratings

Psychologists often systematize their view of a client to clarify impressions of the client, to allow comparison between the client and real or prototypical others, and to assess progress during therapy. Numerous instruments are available for quantifying observer impressions of personality, including several of the measures considered above (e.g., the NEO PI-R). A number of rating scales are also used for this purpose. For example, the Structured Interview for the Five-Factor Model of personality (SIFFM) is a 120-item semistructured interview that provides measures of maladaptive and adaptive aspects of the five factors. The SIFFM is particularly targeted at the measurement of personality disorders and related pathology.

The Q-sort is one noteworthy approach to the use of rating scales. A Q-sort consists of a set of ratings in which comparisons are made ipsatively, or between characteristics (e.g., Fred is more aggressive than he is ambitious). This contrasts with the more typical practice of making normative comparisons, which are comparisons between people (e.g., Fred is more aggressive than Erik).

Several personality measures use the Q-sort methodology. The California Q-set includes 100 items derived from clinical use. Raters are asked to assign items to7to9 categories. Items assess numerous aspects of personality and defensive style (e.g., “Appears to have a high degree of intellectual capacity,” “Is uncomfortable with uncertainty and complexity,” and “Anxiety and stress find outlet in bodily symptoms”). Versions for describing both adults and children are available. A longer Q-set, the Shedler-Westen Assessment Procedure (SWAP-200), has been advanced as well. Q-sets are time consuming to complete because they require a series of paired comparisons between items in order to place ratings into a prescribed distribution. The impressive empirical results that have been found with Q-sets suggest that this time may be well spent.

Current and Future Directions in Personality Assessment

Personality assessment is in a period of creative ferment, characterized by the creation of new measures and the revisions of existing ones, driven by advances in technology, and abetted by a culture that views testing, assessment, and accountability largely as instruments for the common good. Yet the contemporary success of personality assessment brings with it risks. For example, the explosion of the Internet has brought online personality measures of unknown validity into millions of homes. In some cases, these unscreened, unvalidated, and widely used measures may bring insight to those seeking self-exploration, but in many cases this will not be true. Unfortunately, public skepticism about the validity of personality tests, once attributable to the claims of astrologers, palmists, and phrenologists, is today encouraged by the widespread availability of amateurish personality inventories.

In formal assessment, no one instrument will be ideal for every application. The function of testing, the interests of the client and counselor, and the contexts of culture and community should guide the selection, and, where needed, the development of measures. People are different, and the tools of personality assessment, properly used, will continue to assist counselors in understanding, capturing, and furthering human individuality.


  1. Caldwell, A. B. (2006). Maximal measurement or meaningful measurement: The interpretive challenges of the MMPI-2 Restructured Clinical (RC) Scales. Journal of Personality Assessment, 87, 193-201.
  2. Costa, P. T., Jr., & McCrae, R. R. (1992). NEO PI-R: Professional manual. Odessa, FL: Psychological Assessment Resources.
  3. Costa, P. T., Jr., & Widiger, T. A. (Eds.). (2002). Personality disorders and the five-factor model of personality (2nd ed., pp. 351-375). Washington, DC: American Psychological Association.
  4. Gough, H. G., with Bradley, P. (1996). CPI manual (3rd ed.). Palo Alto, CA: Consulting Psychologists Press.
  5. Piedmont, R. L., & Ciarrocchi, J. W. (1999). The utility of the Revised NEO Personality Inventory in an outpatient, drug rehabilitation context. Psychology of Addictive Behaviors, 13, 213-226.
  6. Quenk, N. L., Hammer, A. L., & Majors, M. S. (2001). MBTI Step II manual: Exploring the next level of type with the Myers Briggs Type Indicator Form Q. Palo Alto, CA: Consulting Psychologists Press.
  7. Roberts, B. W., Chernyshenko, O. S., Stark, S., & Goldberg, L. R. (2005). The structure of conscientiousness: An empirical investigation based on seven major personality questionnaires. Personnel Psychology, 58, 103-139.
  8. Watkins, C. E., Jr., & Campbell, V. L. (Eds.). Testing and assessment in counseling practice (2nd ed., pp. 45-71). Mahwah, NJ: Lawrence Erlbaum.
  9. Widiger, T. A., & Trull, T. J. (2007). Plate tectonics in the classification of personality disorder: shifting to a dimensional model. American Psychologist, 62, 71-83.
  10. Wood, J. M., Garb, H. N., Lilienfeld, S. O., & Nezworski, M. T. (2002). Clinical assessment. Annual Review of Psychology, 53, 519-543.

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