The Operationalization and Measurement of Identity Formation: A Scoping Review Based on Eriksonian and neo-Eriksonian Perspectives

Identity formation remains a central topic in developmental psychology, yet there is limited clarity regarding how this construct has been operationalized and measured across Eriksonian and neo-Eriksonian traditions. This scoping review maps the operationalization and measurement of identity formation in adolescence and emerging adulthood by examining empirical studies that developed or evaluated instruments grounded in these perspectives. Thirteen operationalizations and eighteen measurement instruments were identified and categorized into identity processes, outcomes, and impacts. All instruments reported evidence of reliability and criterion validity, whereas other validity evidence was less consistent, including content (three), construct (sixteen), convergent (fifteen), and measurement invariance (nine). The findings indicate that identity formation is conceptualized through multiple interrelated constructs rather than a single unitary phenomenon, while remaining grounded in shared theoretical foundations derived from Erikson's and Marcia's work. This review provides an overview of the current measurement landscape and supports informed instrument selection for future research.