Four Functional Roles for Case Studies in Emerging Adulthood Research

Case studies have four functional roles which, if more widely embraced, can help to advance theory and methodology in the study of emerging adults. These functions are case-based theory development, individual-level prediction testing, theory exemplification, and idiographic psychobiography. We describe these functions and provide real and hypothetical examples of each one. We also discuss specifiability - the capacity of a theory to make predictions about, explain, and interpret individuals - as a criterion of validity for theories that is closely tied to the rationale for case studies. Finally, protocols for case study sampling are described, including intensity sampling, deviant case sampling, and significant case sampling.