Sleep quality is a central diagnostic criterion for insomnia and is widely used by researchers. Yet the construct remains poorly defined and inconsistently operationalized across the literature. Sleep quality is often defined only by its operationalization which can occur at the objective (polysomnography-derived parameters) or subjective (self-report questionnaires) level. Therefore, this thesis aims to examine how sleep quality is currently defined and to explore how commonly used subjective and objective operationalizations relate to one another. 

For this, we will first conduct a brief overview of how sleep quality has been defined over the past five years in two top-tier sleep journals. Second, we will conduct a network analysis and explore cross-level conditional associations between subjective and objective operationalizations of sleep quality. By mapping the structural relationships between these measures, this project aims to provide a foundation for a more precise conceptualization of sleep quality.