To determine how learners and physicians engaged in various structured interventions to inform self-assessment, how they perceived and used self-assessment in clinical learning and practice, and the components and processes comprising informed self-assessment and factors that influence these.This was a qualitative study guided by principles of grounded theory. Using purposive sampling, eight programs were selected in Canada, the United States, the United Kingdom, the Netherlands, and Belgium, representing low, medium, and high degrees of structure/rigor in self-assessment activities. In 2008, 17 focus groups were conducted with 134 participants (53 undergraduate learners, 32 postgraduate learners, 49 physicians). Focus-group transcripts were analyzed interactively and iteratively by the research team to identify themes and compare and confirm findings.Informed self-assessment appeared as a flexible, dynamic process of accessing, interpreting, and responding to varied external and internal data. It was characterized by multiple tensions arising from complex interactions among competing internal and external data and multiple influencing conditions. The complex process was evident across the continuum of medical education and practice. A conceptual model of informed self-assessment emerged.Central challenges to informing self-assessment are the dynamic interrelationships and underlying tensions among the components comprising self-assessment. Realizing this increases understanding of why self-assessment accuracy seems frequently unreliable. Findings suggest the need for attention to the varied influencing conditions and inherent tensions to progress in understanding self-assessment, how it is informed, and its role in self-directed learning and professional self-regulation. Informed self-assessment is a multidimensional, complex construct requiring further research.