Although there is a growing interest in the concept of sense of personal agency in adolescence and young adulthood, its operationalization and assessment have been inconsistent. We propose and test a preliminary assessment model of sense of agency combining four of the most relevant indicators suggested by the literature for its assessment (setting goals, optimism, decision-making, and self-efficacy). We conducted three independent studies with young adults [study 1 = 692; study 2 = 410] and adolescents [study 3 = 481] to analyze its psychometric properties. The CFA results revealed a good fit to the data in all three studies. The results of studies 1 and 2 indicate that even though the four dimensions share a significant proportion of variance, they do not assess the overlapping aspects of sense of agency. The findings of study 1 clarified that the proposed measurement model is invariant across sex and different levels of psychosocial risk. The results of study 2 suggest that, as expected, the latent construct of sense of agency is linked to different dimensions of psycho-emotional adjustment of young adults. Lastly, the findings of study 3 revealed that our preliminary model is invariant across three assessment points establishing the measurement longitudinal invariance
