Validation of the Pemberton Happiness Index (PHI) for the Portuguese population

Abstract

Introduction Given the attention that well-being has received worldwide as being a crucial aspect of the overall health of individuals, its measurement has become increasingly important. Thus, the need for validation of brief and integrative instruments that assess the levels of well-being in the population has emerged. Objective: Contribute to the cultural adaptation and psychometric validation of the Pemberton Happiness Index (PHI) for the Portuguese population. Material and Methods: The study was carried out using a convenience sample of 1,728 individuals whose responses were collected online and by paper. Internal consistency, test-retest reliability, and construct, content, and criterion validity were analysed. Results: The sample consisted mainly of women (n = 1,185), with a mean age of 20.04 ± 20.38 years. The internal consistency of the PHI was very good (α = 0.90), as well as test-retest realibility, with r = 0.79 and p ≤ 0.01 for the correlation between totals and with values ranging from [0.20, 0.46] in Section A and [-0.05, 0.69] in Section B. In the construct validity, only Item 10 of Section A presented values lower than the standard values, which puts into question the validity of this item. Criterion validity had a high correlation (r = 0.75; p ≤ 0.01) when compared to the Warwick-Edinburgh Mental Well-Being Scale (WEMWBS). Conclusion: Considering the good psychometric properties obtained in this study, this instrument can contribute to advancing the complex task of measuring well-being, as well as monitoring and assessing changes at these levels.