Exploring cutoff points and measurement invariance of the Brunnsviken brief quality of life inventory.

Introduction: Quality of life (QoL) can be defined as the goodness of life, beyond simply absence of disease or functional impairments, self-rating scales of which capture valuable information beyond change in primary outcomes. This study ( Method: Confirmatory factor analysis (CFA) models were fit to sample data obtained from an ongoing study on transdiagnostic internet-based treatment modules. Parameters were successively constrained to assess configural, metric, scalar, and residual invariance factor structures across different groups. Results: The BBQ demonstrated MI at the metric level and partial MI at the scalar level across all these groups, which remained stable at the strict-residual level for all groups except for genders. These results remained stable after correcting for unbalanced group sizes for gender, clinical-subclinical levels of depression, and clinical-subclinical levels of anxiety. A cutoff point analysis revealed that a BBQ total scores below 39 was associated with notable psychopathology. Discussion: The BBQ is a reliable measure of QoL that is applicable for various divergent groups (e.g., vulnerable persons), and thus a viable instrument for use in healthcare and research with minimal aversive impact.