Adaptation and Incremental Validity of the Pemberton Happiness Index: A New Measure of Integrative well-being for People with Intellectual Disabilities

ABSTRACT

Introduction

The assessment of well-being is crucial for measuring the effects of psychosocial interventions in people with intellectual disabilities. The aim of this study was to adapt and validate a measure of integrative well-being, the Pemberton Happiness Index (PHI) to use it specifically for this population.

Methods

The Pemberton Happiness Index was first tailored to individuals with intellectual disabilities (PHI-Intellectual Disabilities). Then a sample of 130 adults with mild-moderate intellectual disabilities completed this adapted version alongside other well-being and affective measures.

Results

The psychometric properties of this new PHI-Intellectual Disabilities were shown to be very good (i.e., internal consistency, convergent and incremental validity).

Conclusion

The study provides initial evidence of the reliability and validity of a brief measure of well-being that can be used for both applied and research purposes specifically for adults with mild-moderate intellectual disabilities.

KEYWORDS:

• Psychological well-being
• quality of life
• intellectual disabilities
• measurement

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

¹ Two independent-samples t-tests were conducted to check that the general sample and the subsample were equivalent in well-being levels. There was no significant difference in scores for PHI-Intellectual Disabilities in the general sample (M = 3.03, SD = .63) and the subsample (M = 3.01, SD = .63; t = 2.52, p = .80, two-tailed). Regarding Emotional Well-being, there was no significant difference in scores in the general sample (M = 27.58, SD = 4.46) and the subsample (M = 27.92, SD = 4.69; t = −.56, p = .58, two-tailed).

² For avoiding collinearity problems.