Internal validity refers to how well a study is conducted and focuses on accuracy by controlling extraneous variables and eliminating alternative explanations. External validity relates to how applicable a study's findings are to the real world and focuses on whether results are generalizable and can be translated to other contexts. Together, internal and external validity are two key criteria that Campbell and Stanley identified for evaluating the strength of research designs.

1. INTERNAL AND EXTERNAL
VALIDITY
DIFFERENCES

2. Campbell and stanley
(1966)
 Two general criteria of research designs
 INTERNAL VALIDITY
 EXTERNAL VALIDITY

4. DEFINITION
Internal validity relates to how well a
study is conducted

5. INTERNAL VALIDITY
Focus on
Accuracy

6. INTERNAL VALIDITY
Focus on accuracy and a strong
research method
Controls extraneous variables
Conclusion are warranted
Eliminates alternative explanations

7. DEFINITION
External validity relates to How Applicable
the findings are to the real world

8. EXTERNAL VALIDITY
Findings are
generalizable

9. EXTERNAL VALIDITY
Results translate to world at large
Findings are generalizable
Outcome apply to practical
situations
Results can be translated into
another context