1. Personality Assessment, Measurement and Research Design
Chapter 2
Personality Assessment, Measurement and Research Design

2. How Important is Personality?

3. Sources of Personality Data
Self-Report Data (S-Data)
Observer-Report Data (O-Data)
Test-Data (T-Data)
Life-Outcome Data (L-Data)

4. Self-Report Data (S-Data)
Information a person reveals
Limited by accuracy of information due to self-presentation and self-knowledge
Individuals have access to a wealth of information about themselves that is inaccessible to anyone else

5. Self-Report Data Self-report can take a variety of forms
Unstructured items—open-ended
Structured items—response options provided

6. Self-Report Data Limitations of S-data People may not respond honestly
People may lack accurate self-knowledge

7. Observer-Report Data (O-Data)
Information provided by someone else (e.g. friends, family) about a person
Advantages of O-data
Provides access to information not attainable through other sources
Multiple observers can be used to assess a person

8. Observer-Report Data Selection of Observers
Professional personality assessors
People who actually know the target person
Often in better position to observe target’s natural behaviour than professional personality assessors
Allows for assessment of multiple social personalities
Because of relationship to target, however, observer may be biased

9. Observer-Report Data Naturalistic vs Artificial Observation
Naturalistic observation: Observers witness and record events that occur in the normal course of the lives of the participants
Artificial observation: Occurs in artificial settings or situations

10. Observer-Report Data
Naturalistic observation has the advantage of being able to secure information in a realistic context, but at the cost of not being able to control events and behavioural samples witnessed
Artificial observation has the advantage of controlling conditions and eliciting relevant behaviour, but at the cost of sacrificing realism of everyday life

11. Test-Data (T-Data)
Information provided by standardized tests or testing situations
The idea is to see if different people react differently to an identical situation
Situation designed to elicit behaviours that serve as indicators of personality

12. Test-Data Limitations
Participants might try to guess what trait is being measured and then alter their behaviour to create certain impressions
Difficult to know if participants define testing situation as intended by the experimenter
Researcher might influence how participants behave

13. Test-Data
Can be designed to elicit behaviour that would be difficult to observe in everyday life
Allow investigators to control the context and to eliminate extraneous sources of influence
Enable experimenters to test specific hypotheses by exerting control over the variables that are presumed to have causal influence

14. Test-Data
Mechanical recording devices, e.g. ‘Actigraph’ used to assess children’s activity
Strengths
Not hampered by biases of human observer
May be used in naturalistic settings
Disadvantage
Few personality dispositions lend themselves to mechanical assessment

15. Test-Data Physiological data
Include information about a person’s level of arousal, reactivity to stimuli—potential indicators of personality
Functional magnetic resonance imaging (fMRI)—provides insight into the activity of different brain regions that can be linked with personality dispositions

16. Test-Data Physiological data
Key benefit is that it is difficult to fake responses
Disadvantages
Often used in artificial laboratory setting

17. Test-Data Projective Techniques
Person presented with a standard but ambiguous stimuli and asked to describe what he or she sees; assumption is that person ‘projects’ personality onto ambiguous stimuli

18. Projective Techniques

19. Test-Data Projective Techniques
Strengths: May provide useful means for gathering information about wishes, desires, fantasies and conflicts that a person is not aware of and could not report
Disadvantages: Difficult to score, uncertain validity and reliability

20. Life-Outcome Data (L-Data)
Information that can be gleaned from events, activities and outcomes in a person’s life and which is available for public scrutiny, e.g. marriage, speeding tickets
Can serve as important source of real-life information about personality but personality characteristics represent only one set of causes of life outcomes

21. Issues in Personality Assessment
Links among different data sources
Interpreting links between sources of personality data depends on the research question being posed
Fallibility of personality measurement
All sources of data have limitations
Results that transcend data sources—’triangulation’—are most powerful

22. Issues in Personality Assessment
Aggregation
Adding up, averaging several observations can cancel out transient, momentary events
Disadvantages include making questionnaires more tedious, discouraging participation

23. Evaluation of Personality Measures
Reliability
Validity
Generalizability

24. Reliability
Degree to which an obtained measure represents ‘true’ level of trait being measured
Types of reliability
Test-retest reliability
Internal consistency reliability
Inter-rater reliability

25. Response Sets
Tendency of some people to respond to the questions on a basis that is unrelated to the question content (non-content responding)
Acquiescence
Extreme responding
Social desirability

26. Validity Degree to which test measures what it claims to measure
Types of validity
Face validity
Predictive or criterion validity
Convergent validity
Discriminant validity
Construct validity

27. Generalizability
Degree to which measure retains validity across different contexts, including different groups of people and different conditions
Scales have high generalizability to the degree that they apply widely across different persons, situations, cultures and times

28. Development of Measurement Instruments
Scale Development
Conceptual definition is a must, followed by constructing items
Test the items in focus groups
Scale Diagnostics
Investigate the reliability and validity of items using statistics

29. Research Designs in Personality
Experimental Methods
Correlational Studies
Case Studies

30. Experimental Methods
Used to determine causality—whether one variable causes another
Two key requirements:
Manipulation of variable(s)
Ensuring that participants in each experimental condition are equivalent to each other at the beginning of the study

31. Correlational Studies
Correlation is a statistical procedure for determining whether there is a relationship between two variables
Designed to identify ‘what goes with what’ in nature
Major advantage is that it allows us to identify relationships among variables as they occur naturally

32. Correlational Studies
Correlation coefficient varies from –1 (perfect negative relationships) through 0 (no relationship) to +1 (perfect positive relationship)
Correlation does not indicate causation
Directionality problem
Third variable problem

33. Case Studies In-depth examination of the life of one person Advantages
Can find out about personality in great detail
Can give insights into personality that can be used to formulate a more general theory that is tested on a larger sample
Can provide in-depth knowledge about an outstanding figure

34. Case Studies
A disadvantage is that results based on the study of a single person cannot be generalized to others
Therefore, most often used as a source of hypotheses and as a means to illustrate a principle by bringing it to life

35. When to Use Experimental, Correlational and Case Study Designs
Experiments—ideally suited for establishing causal relationships among variables
Correlational designs—ideally suited for establishing the relationships between two or more variables occurring in everyday life
Case studies—ideally suited for generating hypotheses that can be tested subsequently

36. Summary and Evaluation
Four major sources of personality data (S-data, O-data, T-data and L-data)
Decisions about data source and research design depend on the purpose of the investigation
There are no perfect methods or designs
But some data sources and some methods are better suited for some purposes than for others

37. Let’s Observe Personality

38. Critical Thinking Question #4
Pick two personality characteristics from this list: Openness; agreeableness Now, describe how you could measure this personality characteristic. You may use ANY technique described in the lecture – but you MUST be specific!