Views on Internal and External Validity in Empirical Software Engineering

Abstract

Empirical methods have grown common in software engineering, but there is no consensus on how to apply them properly. Is practical relevance key? Do internally valid studies have any value? Should we replicate more to address the tradeoff between internal and external validity? We asked the community how empirical research should take place in software engineering, with a focus on the tradeoff between internal and external validity and replication, complemented with a literature review about the status of empirical research in software engineering. We found that the opinions differ considerably, and that there is no consensus in the community when to focus on internal or external validity and how to conduct and review replications.