A personality test is a method of assessing human personality constructs. Most personality assessment instruments (despite being loosely referred to as "personality tests") are in fact introspective (i.e., subjective) self-report questionnaire (Q-data, in terms of LOTS data) measures or reports from life records (L-data) such as rating scales.Cattell R.B. (1973). Personality and Mood by Questionnaire. San Francisco, CA: Jossey-Bass. .Cattell, R.B., & Kline, P. (1977). The Scientific Analysis of Personality and Motivation. New York: Academic Press. Attempts to construct actual performance tests of personality have been very limited even though Raymond Cattell with his colleague Frank Warburton compiled a list of over 2000 separate objective tests that could be used in constructing objective personality tests.Cattell, R.B., & Warburton, F.W. (1967). Objective Personality and Motivation Tests: A Theoretical Introduction and Practical Compendium. Champaign, IL: University of Illinois Press. One exception, however, was the Objective-Analytic Test Battery, a performance test designed to quantitatively measure 10 factor-analytically discerned personality trait dimensions.Cattell, R.B., & Schuerger, J.M. (1978). Personality Theory in Action: Handbook for the O-A (Objective-Analytic) Test Kit. Champaign, Illinois: Institute for Personality and Ability Testing. .Schuerger, J.M. (2008). The Objective-Analytic Test Battery. In G.J. Boyle, G. Matthews, & D.H. Saklofske. (Eds.), The SAGE Handbook of Personality Theory and Assessment: Vol. 2 – Personality Measurement and Testing (pp. 529-546). Los Angeles, CA: Sage Publishers. . A major problem with both L-data and Q-data methods is that because of item transparency, rating scales, and self-report questionnaires are highly susceptible to motivational and response distortion ranging from lack of adequate self-insight (or biased perceptions of others) to downright dissimulation (faking good/faking bad) depending on the reason/motivation for the assessment being undertaken.Boyle, G.J. (1985). Self-report measures of depression: Some psychometric considerations. British Journal of Clinical Psychology, 24, 45-59.Boyle, G.J., & Helmes, E. (2009). Methods of personality assessment. In P.J. Corr & G. Matthews (Eds.), The Cambridge Handbook of Personality Psychology (pp. 110-126). Cambridge, UK: Cambridge University Press. .Boyle, G.J., Saklofske, D.H., & Matthews, G. (2015). (Eds.), Measures of Personality and Social Psychological Constructs. Amsterdam: Elsevier/Academic Press. . .
The first personality assessment measures were developed in the 1920s and were intended to ease the process of personnel selection, particularly in the armed forces. Since these early efforts, a wide variety of personality scales and questionnaires have been developed, including the Minnesota Multiphasic Personality Inventory (MMPI), the Sixteen Personality Factor Questionnaire (16PF), the Comrey Personality Scales (CPS), among many others.Boyle, G.J., Matthews, G., & Saklofske, D.H. (2008). (Eds.), The SAGE Handbook of Personality Theory and Assessment: Vol. 1 - Personality Theories and Models. Los Angeles, CA: Sage Publishers. Boyle, G.J., Matthews, G., & Saklofske, D.H. (2008). (Eds.), The SAGE Handbook of Personality Theory and Assessment: Vol. 2 - Personality Measurement and Testing. Los Angeles, CA: Sage Publishers. Although popular especially among personnel consultants, the Myers–Briggs Type Indicator (MBTI) has numerous psychometric deficiencies.Boyle, G.J. (1995). Myers-Briggs Type Indicator (MBTI): Some psychometric limitations. Australian Psychologist, 30, 71-74. More recently, a number of instruments based on the Five Factor Model of personality have been constructed such as the Revised NEO Personality Inventory.Costa, P.T., & McCrae, R.R. (1985). The NEO Personality Inventory Manual. Odessa, FL: Psychological Assessment Resources. However, the Big Five and related Five Factor Model have been challenged for accounting for less than two-thirds of the known trait variance in the normal personality sphere alone.Boyle, G.J. (2008). Critique of Five-Factor Model (FFM). In G.J. Boyle, G. Matthews, & D.H. Saklofske. (Eds.), The SAGE Handbook of Personality Theory and Assessment: Vol. 1 - Personality Theories and Models. Los Angeles, CA: Sage Publishers. Cattell, R.B. (1995). The fallacy of five factors in the personality sphere. The Psychologist, 8, 207-208.Eysenck, H.J. (1992). Four ways five factors are not basic. Personality and Individual Differences, 13, 667-673.
Estimates of how much the personality assessment industry in the US is worth range anywhere from $2 and $4 billion a year (as of 2013). Personality assessment is used in wide a range of contexts, including individual and relationship counseling, clinical psychology, forensic psychology, school psychology, career counseling, employment testing, occupational health and safety and customer relationship management.
History
The origins of personality assessment date back to the 18th and 19th centuries, when personality was assessed through phrenology, the measurement of bumps on the human skull, and physiognomy, which assessed personality based on a person's outer appearances. Sir Francis Galton took another approach to assessing personality late in the 19th century. Based on the lexical hypothesis, Galton estimated the number of adjectives that described personality in the English dictionary. Galton's list was eventually refined by Louis Leon Thurstone to 60 words that were commonly used for describing personality at the time. Through factor analyzing responses from 1300 participants, Thurstone was able to reduce this severely restricted pool of 60 adjectives into seven common factors.Thurstone, L. L. (1947). Multiple Factor Analysis. Chicago, IL: University of Chicago Press. This procedure of factor analyzing common adjectives was later utilized by Raymond Cattell (7th most highly cited psychologist of the 20th Century—based on the peer-reviewed journal literature), who subsequently utilized a data set of over 4000 affect terms from the English dictionary that eventually resulted in construction of the Sixteen Personality Factor Questionnaire (16PF) which also measured up to eight second-stratum personality factors.Cattell, R.B., & Nichols, K.E. (1972). An improved definition, from 10 researches, of second order personality factors in Q data (with cross-cultural checks). Journal of Social Psychology, 86, 187-203. Of the many introspective (i.e., subjective) self-report instruments constructed to measure the putative Big Five personality dimensions, perhaps the most popular has been the Revised NEO Personality Inventory (NEO-PI-R) However, the psychometric properties of the NEO-PI-R (including its factor analytic/construct validity) has been severely criticized.Boyle, G.J., Stankov, L., & Cattell, R.B. (1995). Measurement and statistical models in the study of personality and intelligence. In D.H. Saklofske & M. Zeidner (Eds.), International Handbook of Personality and Intelligence (pp. 417-446). New York: Plenum.
Another early personality instrument was the Woodworth Personal Data Sheet, a self-report inventory developed for World War I and used for the psychiatric screening of new draftees.
Overview There are many different types of personality assessment measures. The self-report inventory involves administration of many items requiring respondents to introspectively assess their own personality characteristics. This is highly subjective, and because of item transparency, such Q-data measures are highly susceptible to motivational and response distortion. Respondents are required to indicate their level of agreement with each item using a Likert scale or, more accurately, a Likert-type scale. An item on a personality questionnaire, for example, might ask respondents to rate the degree to which they agree with the statement "I talk to a lot of different people at parties" on a scale from 1 ("strongly disagree") to 5 ("strongly agree").
Historically, the most widely used multidimensional personality instrument is the Minnesota Multiphasic Personality Inventory (MMPI), a psychopathology instrument originally designed to assess archaic psychiatric nosology.Helmes, E., & Reddon, J.R. (1993). A perspective on developments in assessing psychopathology: A critical review of the MMPI and MMPI-2. Psychological Bulletin, 113, 453-471.
In addition to subjective/introspective self-report inventories, there are several other methods for assessing human personality, including observational measures, ratings of others, projective tests (e.g., the TAT and Ink Blots), and actual objective performance tests (T-data).
Topics
Norms The meaning of personality test scores are difficult to interpret in a direct sense. For this reason substantial effort is made by producers of personality tests to produce norms to provide a comparative basis for interpreting a respondent's test scores. Common formats for these norms include percentile ranks, z scores, sten scores, and other forms of standardized scores.
Test development A substantial amount of research and thinking has gone into the topic of personality test development. Development of personality tests tends to be an iterative process whereby a test is progressively refined. Test development can proceed on theoretical or statistical grounds. There are three commonly used general strategies: Inductive, Deductive, and Empirical. Scales created today will often incorporate elements of all three methods.
Deductive assessment construction begins by selecting a domain or construct to measure. The construct is thoroughly defined by experts and items are created which fully represent all the attributes of the construct definition. Test items are then selected or eliminated based upon which will result in the strongest internal validity for the scale. Measures created through deductive methodology are equally valid and take significantly less time to construct compared to inductive and empirical measures. The clearly defined and face valid questions that result from this process make them easy for the person taking the assessment to understand. Although subtle items can be created through the deductive process, these measure often are not as capable of detecting lying as other methods of personality assessment construction.
Inductive assessment construction begins with the creation of a multitude of diverse items. The items created for an inductive measure to not intended to represent any theory or construct in particular. Once the items have been created they are administered to a large group of participants. This allows researchers to analyze natural relationships among the questions and label components of the scale based upon how the questions group together. Several statistical techniques can be used to determine the constructs assessed by the measure. Exploratory Factor Analysis and Confirmatory Factor Analysis are two of the most common data reduction techniques that allow researchers to create scales from responses on the initial items.
The Five Factor Model of personality was developed using this method. Advanced statistical methods include the opportunity to discover previously unidentified or unexpected relationships between items or constructs. It also may allow for the development of subtle items that prevent test takers from knowing what is being measured and may represent the actual structure of a construct better than a pre-developed theory. Criticisms include a vulnerability to finding item relationships that do not apply to a broader population, difficulty identifying what may be measured in each component because of confusing item relationships, or constructs that were not fully addressed by the originally created questions.