1. Evaluating Research
Is this valid research?

2. External Validity
The extent to which the results of the study apply from the sample to the population, across measurements, contexts, and to the real world (ecological validity)
External validity asks:
Do the results of this study apply beyond the boundaries of the people and measurements and context used in this study?

3. EXTERNAL VALIDITY
The extent to which experimental results generalize...
...to the “real world”
...from sample to the population
...from study to study & with variation

4. Establishing External Validity
Sample issues
Random Selection
Large Participant Pool

5. College Sophomore Problem
Refers to “the worry that, because college sophomores are the subjects in an extremely large number of psychological investigations, the generality of the results is in question”
Keith Stanovich, How to Think Straight about Psychology, p. 115.

6. College Sophomore NOT-a- Problem
Using college sophomores does not invalidate the results, but may limit the results
Many of the processes are basic (and thus, universal to all)
Replication across campuses and outside of the college campus reduces this problem
Adapted from Keith Stanovich, How to Think Straight about Psychology, p. 116.

7. Establishing External Validity
Sample issues
Random Selection
Large Participant Pool
Basic Research (vs. Applied Research)
Does the research apply to the real world?
Replication (for external validity purposes)
Multiple Measures
Does the effect happen in a different context?

8. Internal Validity & External Validity

9. Internal Validity & External Validity