Reliability and factorial validity of long and brief versions of the inventory of personality organization in a Latvian sample

The aim of this study was to examine the construct validity and reliability of long and brief versions (57 and 16 items) of the inventory of personality organization (IPO) in a Latvian nonclinical sample. The actuality of this study is dictated by the number of persons suffering from personality disorders, and the excessive need for reliable constructs for the assessment of personality in the normality-abnormality range. The total number of participants of the study was 1118, recruited in several subsamples, which were employed for the investigation of the factor structure, psychometric properties, test-retest, and convergent validity of the IPO-57 and IPO-16 scales. The 3-factor structure, obtained by confirmatory factor analysis, was replicated in the Latvian-speaking sample for long and brief IPO versions. Both constructs achieved adequate model fit psychometric indices and sufficient internal consistency, and the test-retest reliability was also approved. The convergent validity of IPO with aggressivity, negative affectivity, and non-adaptive personality measures was established. In the current study, we adapted a very fundamental psychodynamic/psychoanalytic construct in the Latvian language and replicated the previously empirically established IPO three-dimensional model, whereas the novelty in IPO construct convergent validity research was the establishment of convergent validity with non-adaptive personality traits measured by the Personality Inventory for DSM-5 Brief Form (PID-5-BF). Both versions of IPO are recommended for further use in the research in Latvian language samples, for clinical purposes to assess the level of psychic functioning, and for treatment planning and evaluation purposes.