Personality Assessment

domains of personality assessment

organisational, clinical, educational, counselling and forensic psych

problems with measuring personality

• appear subjective

• no infallible source of info about the person

• ‘object’ knows it is being measured

• traits are not directly observable

2 concepts that influence how well personality is measured

• reliability - does the measurement yield consistent, dependable and error-free info

• validity - does the measurement assess what is intended to assess and is it useful

3 varieties of reliability

• internal consistency - do the components of the test all cohere and all test items should correlate with one another

• inter-rater reliability - does the test provide same info about the person when diff people administer it

• re-test reliability - does test yield sim scores when administered to same person on diff occasions

3 kinds of measurement error

within the test, between testers and over time

relationship between reliability consistency and error

high reliability = high consistency = low error

2 components of validity

• does the test measure what is intended to measure

• does the test provide practically useful info

does the test measure what is intended to measure

• content validity

• convergent validity

• discriminant validity

does the test provide practically useful info

predictive validity

a good test of trait X involves

• all items should intercorrelate

• same score should occur whoever gives it

• pp should get sim scores when they do it twice

• all items should clearly relate to meaning of X

• should correlate strongly with other measures of X

• should not correlate with measures of Y and Z

• should correlate with things that X is related to 

when does unreliability exist

when there is inconsistency in what the test measures (scattered)

when does invalidity exist

when the test does not measure what it should (targeting the bullseye)

modes of personality assessment

• interviews

• personality inventories

• projective tests

• implicit personality tests

interviews

rarely used as time and labour intensive, subjective (poor inter-rater reliability), prone to biases:

• halo effect

• self-fulfilling prophecy

• confirmation bias

when are interviews used

assessing attributes where the person may not be a reliable informant and/or where interpersonal and nonverbal behaviour may be revealing e.g. personality disorders

forms of interviews

• structured

• unstructured

• semi-structured - combines structure and flexibility

• provocative - type A personality

personal inventories

self-report tests composed of multiple items which form scales

• omnibus tests with many scales

• single-scale tests

• gen at least 10 items per scale

response scales including true/false and likert scale

inventory development

• item generation

• pilot testing

• item analysis - check internal consistency and factor analysis 

• select optimal items for final scale

• re-test on new sample

• correlate with other tests and prediction criteria

• develop norms to allow score comparison

problems with self-report

vulnerable to response biases and limitations of self-knowledge. longer tests include validity scales to check for this

• lie scales

• infrequency scales

• defensiveness scales

• inconsistency scales

MMPI

e.g. of inventory.1940s - for comprehensive clinical personality assessment. 10 clinical scales, 3 validity scales and 566 items

MMPI 4/8 code

indicates high scores in Psychopathic Deviate and Paranoia scales = 

• non-conforming

• odd

• avoid close relationships

most common diagnoses are schizophrenia and schizoid personality

projective tests

developed to bypass problems of self-report by aiming to penetrate to deeper levels of personality. involves deliberate ambiguity and open-endedness

• ambiguous stimuli

• unstructured responses

based on assumption that personality will be projected onto stimuli without defensive distortions operating

thematic apperception test

projective, Murray. idiographic approach using series of monochromatic images where person tells extended story about whats happening in pic. responses coded for repeated themes in stories - motives attributed to protagonists, interpersonal conflict, ways of handling conflict

thematic apperception test

projective, few widely accepted scoring = recipe for inter-scorer unreliability but

• rigorous scoring for defence mechanisms - denial and projection (Cramer)

• motives - need for achievement (McClelland)

Rorschach Test

projective, series of symmetrical inkblots and person says what object/s the person sees (percept) and what aspects of the blot lead them to see it. scored on numerous dimensions

example codes for Rorschach Test

• use of full image

• use of details

• use of space

• popular responses

• form quality - goodness of fit of percept to image contours

• unusual details selected

• movement - dynamic activity classified as human, animal or inanimate

• shading

• texture

• response to colour

interpretations according Rorschach scoring - number of responses

• low = depression, intellectual disability

• high = manic tendencies

interpretations according Rorschach scoring - whole vs detail

• whole = healthy capacity to integrate

• detail:

• common = practicality, possible OCD

• uncommon = higher in severe mental disorder

critiques of projective tests

• time consuming

• encourages wild unconstrained interpretation

• low inter-scorer reliability

• predictive validity is gen weak compared to self-report tests

• often little incremental validity beyond self-report tests

implicit tests

based on rapid automatic responses, in principle difficult to fake and less susceptible to response bias

implicit association test

4 sets of words

• self - me, my

• not-self - they, them

• extraversion - active, confident

• introversion - aloof reserved

2 trials - participants must rapidly classify words into different word pairings e.g. self introvert v not-self extravert (reversed for next trial)