The goals of this project are twofold: First, this project will examine the measurement invariance of the Level of Personality Functioning Scale - Brief Form 2.0 (LPFS-BF 2.0) across a broad range of countries (35 countries) and languages (20 languages), as well as the measurement invariance of the World Health Organization’s Quality of Life Brief Scale (WHOQOL-BREF; WHOQOL Group, 1998), the Personality Disorder Severity ICD-11 scale (PDS-ICD-11; Bach et al., 2021), and the Tightness-Looseness Scale (TLS; Gelfand et al., 2011). The latter measurement invariance investigations are included in this project for the purposes of (a) assessing the suitability of these measures for describing and comparing our samples; (b) assessing their appropriateness as outcome criteria to be used when evaluating the predictive invariance of the LPFS-BF 2.0; and (c) offering evidence pertaining to these instruments’ applicability for international research and application. The second goal of this project is to examine the LPFS-BF 2.0’s predictive invariance regarding three established constructs. The specific constructs were selected based on their well-established associations with personality dysfunction and include quality of life (e.g., Cramer et al., 2006), personality disorder severity (e.g., Bach & Anderson, 2020), and history of mental health services (e.g., Cruitt et al., 2019).