What does external validity refer to, and what design considerations enhance it?

What does external validity refer to, and what design considerations enhance it?

• A. External validity is generalizability to other populations/settings; strategies include diverse samples, real-world settings, and replication.
• B. External validity measures the precision of a sample statistic.
• C. External validity concerns the reliability of measurement instruments.
• D. External validity is the same as internal validity; both come from randomization within a study.

Answer: (A)