Increasing concerns about the policy implications of ageing populations, and increased life expectancies, in the developed world, have led to interest in interventions to improve older people's health, independence, activity, social and economic participation, thereby their active
contribution to society—and also, in effect, adding quality
to extended years. Assessment of the effectiveness of public policy in these areas requires the use of relevant and valid outcome measures. Assessment of quality of life (QoL) is a commonly used end-point of health technology assessment and is the stated end-point of policies aiming to promote active ageing [1
However, the various models of quality of life are not consistent. Some have incorporated a needs-based satisfaction model, based on Maslow [2
] and Maslow [3
] hierarchy of human needs for maintenance and existence (physiological, safety and security, social and belonging, ego, status and self-esteem, and self-actualisation). Higgs et al. [4
] and Hyde et al. [5
] based their model of QoL in older age on self-actualisation and self-esteem. In contrast, traditional U.S. social science models of quality of life have been based primarily on the overlapping, positive, concepts of “the good life,” “life satisfaction,” “social well-being,” “morale” “the social temperature,” or “happiness” [6
]. The focus among psychologists is on psychological resources [9
]. Lack of agreement on a concept of QoL across disciplines has hindered attempts at multidimensional measurement.
Research with older populations has also suffered from the lack of generic QoL instruments that are truly applicable to this group. Investigators of QoL outcomes in older age have commonly applied the Short-From-36 health status questionnaire as a proxy for QoL, although some research suggests that older age groups have higher rates of item nonresponse, than others, with this instrument because they find several items not applicable to them [10
]. The multifaceted nature of QoL has posed particular challenges for measurement. Few measures of QoL are truly multidimensional, while ageing and increased frailty can have effects on several areas of life. As QoL is a largely subjective concept, it is essential to reflect lay views in any instrument designed to measure it. Most existing measures of QoL are based on theoretical concepts such as human need, life satisfaction, broader health, or are individualised and expensive to administer [12
Recent attempts to address this gap in available measurement instruments for use with older people include the development of the CASP-19 and the WHOQOL-OLD. The CASP-19 (19 items) was based on models of needs satisfaction and self-actualisation, and aimed to measure Control, Autonomy, Self-realisation and Pleasure, although there was relatively little lay input into its construction [4
]. The WHOQOL-OLD (24 items) is a module of the World Health Organization's (WHO) broader measure of QoL, the WHOQOL, which was designed for adults of all ages. The WHOQOL-OLD includes additional items, judged by focus groups to be missing from the WHOQOL if applied to older people [13
]. Despite the collection of a large amount of qualitative data, the WHOQOL group made a prior, largely “expert led” decision about the domains for inclusion in the WHOQOL; there was also little indication that the group had drawn on the broader QoL literature in the construction of the measure.
The research presented in this paper intended to shift the paradigm of questionnaire development towards a more constructivist approach embedded firmly in the perspective of the older person, integrated with theory, embracing the epistemological challenge that lay views pose for academic theories. Social investigations can benefit from grounding in lay views, as they provide understandings in terms of cause and meanings, and they are a vehicle for people to reassert their worth (empowerment) [14
]. By prior testing lay views against theoretical models, we also satisfied the condition for the development of measures that they are embedded in theory [15
The QoL Survey, funded by ESRC Growing Older programme, was the first representative study of the QoL of people aged 65+, living at home in Britain. We asked 999 randomly sampled people aged 65+ open-ended interview questions about what gave their lives quality, what took quality away, and their priorities, followed by a self-rated QoL uniscale and a series of structured measures. We also followed-up 80 respondents and asked them about their QoL in-depth. The study was unique in obtaining quantitative and
qualitative data on social, psychological, environmental, health, and personal circumstances from the same
nationally representative sample of people aged 65+ in Britain. The unique, rich dataset led to a lay based, multidimensional
model of social, economic, psychological, health and neighbourhood influences (both positive and negative) on QoL, and which overlapped with theoretical models taken in combination [16
We adopted a multidisciplinary perspective and assessed theoretical influences on QoL using validated, structured measures of social, psychological morbidity, health and functioning, psychological resources, including self-efficacy and control; perceived neighbourhood social capital and facilities in the built environment, including transport, socioeconomic and social circumstances. In our survey, in order to separate these predictor from the component variables of QoL, QoL was considered as unidimensional construct (measured with a global QoL uniscale), but with multiple influences. Respondents emphasised the importance of social and psychological resources, health and functioning, neighbourhood resources, adequate finances and independence for a good QoL. These were categorised as main themes. The meanings underlying these were also coded (as subthemes). They cut across the main themes, emphasising the freedom to do the things they wanted to do without restriction: pleasure, enjoyment, and satisfaction with life; mental harmony; social attachment—having access to companionship, intimacy, love, social contact, and involvement, help; social roles; feeling secure. Respondents' statements which reflected the most commonly occurring themes and subthemes were included in an initial 50-item version of the Older People's Quality of Life Questionnaire (OPQOL). The full version of OPQOL was piloted for face validity and acceptability in focus group interviews and with over 100 volunteers from the original QoL survey respondents. Initial tests of internal consistency (Cronbach's alpha) and construct validity were also conducted at this stage, and which led to item-reduction. This process is described in more detail later under Measures.
The objective of the paper presented here is to describe the full psychometric testing, and psychometric properties, of the Older People's Quality of Life Questionnaire (OPQOL), and compare it with the CASP-19 and WHOQOL-OLD in samples of older people in the British population and an ethnically diverse sample.