Personality assessment, measurement, and research methods |  |
Chapter OutlineSources of Personality Data
Self-Report Data (S-Data)
- Information provided by a person, such as through a survey or interview
- Individuals have access to a wealth of information about themselves that is inaccessible to anyone else
- S-data personality tests
- Unstructured items—open-ended
- Structured items—response options provided
- Limitations of S-data
- People may not respond honestly
- People may lack accurate self-knowledge
Observer-Report Data (O-Data)
- Information provided by someone else about another person
- Key features of O-data
- Provide access to information not attainable through other sources
- Multiple observers can be used to assess a person
- Selecting observers
- Professional personality assessors
- People who actually know the target person
- Often in better position to observe targetÕs natural behaviors than professional personality assessors
- Allows for assessment of multiple social personalities
- Because of relationship to target, however, observer may be biased
- Naturalistic versus artificial observation
- Naturalistic observation: Observers witness and record events that occur in the normal course of lives of the participants
- Artificial observation: Occurs in artificial settings or situations
- Naturalistic observation has the advantage of being able to secure information in realistic context, but at the cost of not being able to control events witnessed
- Artificial observation has the advantage of controlling conditions and eliciting relevant behavior, but at the cost of sacrificing realism
- Immediate versus retrospective observation
- Immediate observation: Events observed and recorded as they happen
- Retrospective observation: Events recorded after they have happened
- Molar versus molecular units of observation
- Size of the unit selected for observation
- Molar: e.g., global traits of intelligence, emotional stability
- Molecular: e.g., how fast a person walks
- Smaller observational units are assessed with greater precision and greater between-observer agreement, but larger units are often more predictive of relevant outcomes
Test-Data (T-Data)
- Information provided by standardized tests or testing situations
- Idea is to see if different people behave differently in identical situations
- Situation designed to elicit behaviors that serve as indicators of personality
- Elicited behavior ÒscoredÓ without reliance on inference
- Limitations
- Participants might try to guess what trait is being measured and then alter their behavior to create certain impressions
- Difficult to know if participants define testing situation as intended by experimenter
- Researcher might influence how participants behave
- Mechanical recording devices
- ÒActometerÓ used to assess childrenÕs activity
- Strengths
- Not hampered by biases of human observer
- May be used in naturalistic settings
- Disadvantage: few personality dispositions lend themselves to mechanical assessment
- Physiological data
- Includes information about a personÕs level of arousal, reactivity to stimuliÑpotential indicators of personality
- Key benefit is that it is difficult to fake responses
- Disadvantages
- Often used in artificial laboratory setting
- Accuracy of recording hinges on whether participant perceives situation as experimenter intended
- Projective Techniques
- Person presented with ambiguous stimuli and asked to describe what she sees; assumption is that person ÒprojectsÓ personality onto ambiguous stimuli
- Thematic Apperception Test
- Rorschach Inkblot Test
- Draw-a-Person Test
Strengths: May provide useful means for gathering information about wishes, desires, fantasies that a person is not aware of and could not reportDisadvantages: Difficult to score, uncertain validity, and reliabilityLife-Outcome Data (L-Data)
- Information that can be gleaned from events, activities, and outcomes in a personÕs life that is available for public scrutiny—e.g., marriage, speeding tickets
- Can serve as important source of Òreal lifeÓ information about personality
Issues in Personality Assessment
- Links among different data sources—when they do and do not exist and how to interpret these linkages
- Fallibility of personality measurement
- All sources of data have limitations
- Results that replicate through ÒtriangulationÓ (across different data sources) are most powerful
Evaluation of Personality Measures
Reliability
- Degree to which measure represents ÒtrueÓ level of trait being measured
- Types of reliability
- Test-retest reliability: scores at one administration positively correlate with scores at second administration
- Alternate forms reliability: scores on one version of test correlate with scores on parallel but different version of test
- Internal consistency reliability: items within test positively correlate
Validity
- Degree to which test measures what it claims to measure
- Types of validity
- Face validity: whether test appears to measure what it is supposed to measure
- Predictive validity: whether test predicts criteria external to the test that it is expected to predict
- Convergent validity: whether test score correlates with other measures that it should correlate with
- Convergent validity: whether test score does not correlate with other measures it should not correlate with
- Construct validity: subsumes other types of validity; broadest type of validity
Generalizability
Degree to which measure retains validity across different contexts, including different groups of people and different conditionsGeneralizability subsumes reliability and validityGreater generalizability not always better; what is important is to identify empirically contexts in which a measure is and is not applicable
Research Designs in Personality
Used to determine causalityÑwhether one variable causes another
Two key requirements:Manipulation of variablesÑexperimenter manipulates independent variable and measures effects on dependent variableEnsuring that participants in each experimental condition are equivalent to each otherÑaccomplished through random assignmentCorrelation is a statistical procedure for determining whether there is a relationship between two variablesDesigned to identify Òwhat goes with whatÓ in nature, and not designed to identify causal relationshipsMajor advantage is that it allows us to identify relationships among variables as they occur naturallyCorrelation coefficient varies from Ð1 (perfect negative relationships) through 0 (no relationship) to +1 (perfect positive relationship)Correlation does not indicate causationDirectionality problemThird variable problemIn-depth examination of the life of one personAdvantagesCan find out about personality in great detailCan give insights into personality that can be used to formulate a more general theory that is tested on a larger sampleCan provide in-depth knowledge about an outstanding figure, such as a political or religious figureDisadvantagesResults based on the study of single person cannot be generalized to others
When to Use Experimental, Correlational, and Case Study Designs
Each design has strengths and weakness; strength of one is weakness of anotherWhich design a researcher uses depends on the research question and the goal of researchTaken together, three designs provide complementary methods for exploring personality
Summary and Evaluation
Decisions about data source and research design depend on the purpose of studyThere is no perfect data sourceThere is no perfect research design
But some data sources and some methods are better suited for some purposes than for others
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2002 McGraw-Hill Higher Education