extended · article · 2011

Rasch analysis of the International Wellbeing Index in older adults

Maria João Forjaz; Alba Ayala; Carmen Rodríguez‐Blázquez; María-Eugenia Prieto-Flores; Gloria Fernández‐Mayoralas; Fermina Rojo‐Pérez; Pablo Martínez‐Martín; Everett V. Smith Jr.

BACKGROUND: The International Wellbeing Index is a measure of general quality of life formed by two scales: the Personal Wellbeing Index (PWI) and the National Wellbeing Index (NWI). This paper studies the psychometric properties of the PWI and NWI, using Rasch analysis and classic psychometric methods. METHODS: The PWI and NWI were applied to a representative sample of 1106 community-dwelling adults, aged 60 years and over, residing in Spain. Mean ± standard deviation age was 72.07 ± 7.83 years and 56.3% were women. RESULTS: Five PWI items (achieving in life, relationships, safety, community connectedness, and future security), and five NWI items (economic situation, state of environment, social conditions, business, and national security of the country) fitted the Rasch model. After adjusting the response scale format, satisfactory fit was obtained, with good reliability (person separa...