Development of two equivalent short forms of the Psychological General Well-Being Index: PGWBI-A and PGWBI-B

Psychological General Well-Being Index (PGWBI) is a generic health-related quality of life instrument that produces subscale scores about six domains of well-being and a global score. A literature review showed that the factor validity was good for the global score but was poor for the subscale scores. The aim of the study was to develop two short forms of the instrument that produce equivalent global well-being scores. Data gathered from two samples of healthy people coming from the North, the Center, and the South of Italy were employed for the development (N = 428) and for the assessment of measurement invariance (N = 220) of the two forms. Confirmatory factor analysis (CFA) was used to derive the two forms and to test their invariance. The two forms (PGWBI-A and PGWBI-B) showed items' partial measurement invariance and their global scores showed good internal coherence.