1. Chapter 8: Construct and External Validity in Experimental Research
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2. Construct Validity
Definition—extent to which we can infer higher-order constructs for our operations
Constructs are used for
Research participants
Independent variable
Dependent variable
Experimental setting

3. How to Assess Construct Validity
Have a clear definition of the construct of interest
Problem is identifying prototypical features of the constructs
Affects ability to identify the concrete operations used to represent the construct

4. Assess the match between the constructs and the operations used to represent them
Ways to assess
Content validity
Criterion-related validity
Predictive
concurrent

5. Threats to Construct Validity
Inadequate explanation of the construct
Construct confounding
Mono-operation bias
Confounding constructs with level of constructs
Reactive self-report changes
Reactivity to the experimental situation
Experimenter effects

6. Novelty and disruption effects
Compensatory equalization
Compensatory rivalry
Resentful demoralization
Treatment diffusion

7. Reactivity to the Experimental Situation
Refers to research participants motives and perceptions influencing their response to the DV
Motive and perceptions influenced by the demand characteristics of the experiment
Primary motive--positive Self-presentation
Condition producing positive self-presentation motive
Implication for research
Intertreatment interaction
Intratreatment interaction

8. Ways experimenter may bias the study
Experimenter Effect
Experimenter’s motive of supporting the study hypothesis can lead to bias
Ways experimenter may bias the study
Experimenter attributes
Experimenter expectancies
Effect on experimenter—recording bias
Effect on research participant--
Magnitude of expectancies—can exist in animal and human research and can be greater than the IV

9. External Validity
Definition—generalizing across people, settings, treatment variations, outcomes and times
Represents a test of interactions

10. Threats to External Validity
Population validity
Target population
Experimentally accessible population
Requires generalization from sample to target population
Ecological validity
Temporal validity
Seasonal variation
Cyclical variation
Treatment variation validity
Outcome validity

11. External Validity Concerns
Cautions in evaluating external validity
Some studies conducted to increase knowledge and not to generalize to a real life situation
Some studies assess a theoretical process
Moving out of the laboratory does not insure generalization
Relationship between internal and external validity—often an inverse relationship