Over recent years, measures of health status have increasingly opted for measures of subjective health status, that ask the individuals themselves to rate their health. These types of measures are known as quality of life scales. But what is ‘quality of life’? Until quite recently, quality of life was not considered an issue of psychological importance in areas such as chronic illness. But reports of a Medline search on this term indicated surges of its use in many different eras, suggesting that ‘quality of life’ is generally in vogue. But, to date, there is no consensus as to what it actually is.
According to Aaronson, Calais de Silva in 1986, for many years it was measured in terms of the length of a patient’s survival and any signs of a present disease, with no consideration of the psychosocial consequences of illness and treatments. An examination of the research literature of quality of life by S.E. Taylor and Aspinwall in 1990 revealed that medical citations to works that assessed morbidity and mortality outnumbered psychological citations by more than ten to one. Before the 1980s, quality of life was mainly assessed by physicians, and was based on medical criteria rather than the patients’ or relatives’ assessments of quality of life.
In 1990, Grant suggested that it was “a personal statement of the positivity or negativity of attributes that characterise one’s life.” While in 1993, Patrick and Ericson stated that it was “the value assigned to duration of life as modified by the impairments, functional states, perceptions and social opportunities that are influenced by disease injury, treatment or policy.”, and the ‘World Health Organisation Group’ defined it as “a broad ranging concept affected in a complex way by the person’s physical health, psychological state, level of independence, social relationships and their relationship to the salient features in their environment.”
This problem with defining the term has resulted in a range of ways of operationalising quality of life. In 1993, Aaronson discovered that following discussions about an acceptable definition, the ‘European Organisation for Research on Treatment of Cancer’ operationalised quality of life in terms of “functional status, specific cancer and treatment symptoms, psychological distress, social interaction, financial/economical impact, perceived health status and overall quality of life.”
Similarly, researchers such as Stewart and Ware, who worked on the ‘Rand Corporation’ health batteries in 1992 operationalised quality of life in terms of “physical and social functioning, role limitations due to physical and emotional problems, mental health, energy and vitality, pain and general health perception” which formed the basic dimensions of their scale. In 1990, Fallowfield defined the four main dimensions of quality of life as ‘psychological’, such as mood, emotional distress and adjustment to illness, ‘social’, such as relationships and social/leisure activities, ‘occupational’, such as paid and unpaid work, and ‘physical’, including mobility, pain, sleep and appetite.
Due to these problems of defining the concept of quality of life, researchers have attempted to create a clearer conceptual framework for the construct. They divided the quality of life measures according to who devised the measure or in terms of whether the measure is consider objective or subjective. In 1997, Browne differentiated between the standard needs approach and the psychological processes perspective. The first is based on the assumption that “a consensus about what constitutes a good or poor quality of life exists or at least can be discovered through investigation.” It also assumes that common needs, rather than wants, are central to quality of life. In contrast, the psychological processes approach considers quality of life to be “constructed from individual evaluations of personally salient aspects of life.” So Browne saw quality of life measures as being devised by researchers or individuals themselves.
In 1998, Muldoon provided an alternative conceptual framework for quality of life, based on the degree to which the domains being rated were objectively validated. It was argued that quality of life measures should be divided into those that assess objective functioning, the ones that describe an individual’s level of functioning that must be validated against directly observed behavioural performance, and those that assess subjective well-being, describing the individual’s own appraisal of their well-being. So some progress has been made to clarify the problems surrounding measures and quality of life, but an exact definition is still unclear. In 1990, Annes argued that the term should stop being used altogether.
The range of measures that have been developed are considered in terms of undimensional measures such as Goldberg’s ‘General Health Questionnaire’ developed in 1978, the ‘Hospital Anxiety and Depression Scale’ devised by Zigmond and Snaith in 1983, the ‘Beck Depression Scale’ and the ‘McGill Pain Questionnaire’. All of these measures assess one specific aspect of health, and are used in their own or in conjunction with others. Another type of measures are the multidimensional measures that assess health in the broadest sense. Patients are asked simple questions to determine their state of health on a scale rating from ‘poor’ to ‘perfect’. They are also asked to make judgements about their health based on a scale from ‘best possible’ and ‘worst possible’. In 1995 Idler and Kasl discovered that even though they weren’t very detailed, they did correlate highly with more complex measures and can be useful as outcome measures. But, even so, researchers tend to use composite scales.
Many different measures have been developed, due to the fact there are so many ways of defining quality of life. Some focus on particular populations. For example, Lawton investigated the elderly in 1972 and 1975, and people in their last year of life in 1990. Generic measures of quality of life have also been developed, that can be applied to any individual. An examples of this is the ‘Nottingham Health Profile by created by Hunt in 1986. These type of measures have been criticised for being too broad, and therefore result in a definition of quality of life that is too encompassing, vague and unfocused.
In contrast, they have also been criticised for being too focused, and for potentially missing out aspects of quality of life that may be of specific importance to the individual concerned. It is believed that by asking individuals to rate statements that have been developed by researchers and answer a pre-defined set of questions that the individual’s own concerns may be missed. This has led to the development of individual quality of life measures.