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Chapter 5: Developing a Measurement Strategy. Scales of Measurement Reliability and Validity Modalities of Measurement Locating and Evaluating Measures. Reliability & Validity. Why is reliability important? Theory can’t do without it Constructs can’t be valid unless they are reliable
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Chapter 5: Developing a Measurement Strategy • Scales of Measurement • Reliability and Validity • Modalities of Measurement • Locating and Evaluating Measures
Reliability & Validity • Why is reliability important? • Theory can’t do without it • Constructs can’t be valid unless they are reliable • A phenomenon must be reliably demonstrated before it can have construct status • E.g. ESP, Loch Ness Monster • What are some examples of phenomena important to: • Counselors? • I/O psychologists?
Reliability & Validity • Manifest variables: • Directly observable • Hypothetical Constructs: • Not directly observed (inferred) • What are some examples? • Behavioral? • Psychological constructs? • Which types (manifest/hypothetical) are: • Operational definitions? • Hypothetical constructs? • How are Operational definitions and Hypothetical constructs related? • Operational definitions represent hypothetical constructs
Reliability & Validityand measurement error • Reliability & Validity • Reliability – consistency • Validity – accuracy • Polygraph • Reliable and valid? • Can something be reliable but not valid? • Can something be valid but not reliable? • Measurement Error Xo= T+E (Observed score = True score + Error) Randon v. systematic error What kind of error is introduced when an applicant fakes on a personality measure? Other examples?
Assessing Reliability • Forms • Test-retest • Alternate forms (equivalent forms) • Interrater reliability • Internal consistency • Split half • Cronbach’s alpha (coefficient alpha) • mean r among all items • Which one to use? • Give some examples • Standards for reliability • What’s acceptable?
Assessing Validity • Validity • Inferred • Depends on different types of evidence • Varies in how much (degree) • Trichotomized into: high, moderate, low • Specific to what it’s used for (valid for what?) • refers to inferences drawn, not the measure itself • A unitary construct (with three types of evidence) • Content, • criterion-related (predictive, concurrent) • Construct
Validity • Convergent • Related to other constructs it should be related to • Divergent • Not related to other constructs it should not be related to which should be convergent and which divergent? • IQ and Depression • Work motivation and conscientiousness • Happiness and wealth • Need for approval and caring about how one looks • Ability to sell and friendliness • Aggression and frustration level
Validity:Determining Degree of Validity • Measure validation process • See figure 5-4 • Theory of trait • Test hypotheses • Confirm/disconfirm • Do it again • Never ending (seemingly) • Eg. CPI, WGCTA, WPT, NEO, Beck DI
Validity: Differential • Valid for specific population, group? • Moral reasoning? • Different cultures, Gender (Gilligan, ’82)? • Math tests? • Gender? • PONS test? • Gender? • Personality inventories? • Fakers v. honest? • Job setting v. home setting?
Reliability & Validity: Modalities of Measurement • Self-Report Measures • Advantages • Limitations • Behavioral Measures • Advantages • Limitations • Physiological Measures • Advantages • Limitations • Choosing a Measurement Modality
Modalities: • Self-Report • Cognitive • Affective • Retrospective v. Hypothetical (behavioral intention) • Kinesthetic • Advantages • Easy to collect • Easy to administer • Feelings (cannot observe) • Thought process (Policy capturing) • May be more accurate than observation. Why? • Limitations • Accuracy of recall • Willingness to report • Verbal skills needed
Self Report Modalities: • How to • Ask about actual previous behaviors • Use dichotomous or categorical for or behavior or behavioral intentions • Use Likert (5, 7 or 9) for attitudes • Include both positively and negatively scaled items • Use graphic labels or benchmarks • Use multiple items to capture a concept • Avoid leading double barreled questions (usually)
Modalities:Behavioral Measures • Uses • Behavior is object of study • Operational definitions • Nonverbal may be clue to feelings/ physio state • Types of measures • Frequency (bar presses) • Rate • Duration • Intensity • Accuracy • Persistence • Examples?
Behavioral Measures • Advantages • Surreptitious (sneaky) • Avoids evaluation apprehension • Capture automatic behaviors • Often not premeditated • More accurate than behavioral intention • Limitations • “what you see is what you get” What limitation is implied here? • Interpretation is inferred by observer • Highly situation-specific • That’s why R. Hogan likes to use personality trait as predictor • Need trained observers
Modalities: Physiological Measures • Purposes • Of interest in and of itself • As op definition of psychological state • E.g. anxiety, arousal, lying • Advantages • Most direct (no intervening human observer • Highly precise • Limitations • Need equipment, trained administrators • Obtrusive • Constrain freedom • Source of unreliability (testing effects) • E.g. polygraph
Modalities:Choosing & Locating Measurement Modality • Choosing: Self-report, behavioral, physiological • Rank them for level of validity • Which one should be used? • See table 5-2 relative advantages and limitations • Multiple operationism • Categories of Measures (figure 5-7, p. 147) • Type: manifest v. hypothetical • Hypothetical construct: • Psychometric (used for individual scores) • research measures (used for mean scores; norms) • Developed (use when it fits procedure) • Ad hoc (when you have to develop it)
Modalities: Locating & Evlauting Measures • Locating Measures • MMY • (Buros) • Tests in Print • Directory of Unpublished Experimental Measures • (Goldman & Sanders, 1997) • Measures of Personality and Social Psychological Attitudes • (Robinson, Shaver,& Wrightsman, ’91) • Organizational Measures • Warr, Cook and Wall??
Modalities: Evaluating Them • Theoretical Background • How much construct standing? • Quality of Development • Participant samples, norms • Reliability & Validity • What are good coefficients for each? • Valid for what? • Freedom from Response Bias • Social desirability • Acquiescence bias
Developing a Measurement StrategySummary • Scales of Measurement • Reliability and Validity • Modalities of Measurement • Locating and Evaluating Measures