A psychometric evaluation of the Life Essentials Assessment Framework (LEAF-7)

Abstract

Background: The LEAF-7 was designed by reference to the capability perspective by Age UK to measure the quality of life of vulnerable older adults. It was designed to be utilised by trained Age UK assessors who work with service users in order to improve their life circumstances. The aim was to establish whether or not the LEAF-7 was unidimensional and to examine the psychometric characteristics of the individual items. Methods: The LEAF-7 consists of seven domains assessing various aspects of quality of life (e.g. capacity for 'managing health' & 'enjoyment'), measured on a four-point Likert scale. Alongside these domains there is a supplementary life satisfaction item measured on a 7-point Likert scale. For this evaluation 193 Age UK service users completed the LEAF-7 supported by a trained assessor. Findings: Factor and Rasch analysis confirmed that the LEAF-7 was a unidimensional measure with all items correlating significantly with the underlying dimension. Additionally there was high internal reliability as well as excellent stability over time (high test-retest reliability). There were though some issues with the reliability of the rating scale for the supplementary life satisfaction item. Discussion: The analyses showed that the LEAF-7 has excellent psychometric properties and is suitable for use in the assessment of the quality of life of vulnerable older adults. It also demonstrated sensitivity to changes in quality of life over time. It is recommended that caution should be taken in the interpretation of the single life satisfaction item given the reliability issues with this item.