Using multiple methods to improve validity

Abstract Behavioral research faces unique challenges in balancing internal and external validity, especially for policy-oriented studies. This paper examines the limitations of combining experimental and field data to address the “behavioral policy challenge,” highlighting the need for rigorous theoretical assumptions and practical considerations. Drawing on empirical examples, we demonstrate how combining laboratory and field data can sometimes fail to ensure both causality and relevance. We propose criteria for effectively integrating multiple methods to enhance validity, offering insights for researchers aiming to establish robust evidence for behavioral phenomena in policy-making contexts.