Evaluating Patient-Based Outcome Measures - NIHR Health ...

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What are patient-based outcome measures?
number of such discussions of the theoretical basis
of, say, QoL (Rosenberg, 1995; Rogerson, 1995).
These theories also generate definitions, each
with distinctive emphases. This can be seen from
an illustrative list of definitions and discussions of
health and health-related QoL that have been cited
as useful in this field (Box 2). The literature is
replete with such definitions accompanied by
BOX 2 Illustrations of range of definitions and
discussions of health and QoL
• Health as a ‘state of complete physical, mental and
social well-being and not merely the absence of
disease or infirmity.’ (WHO, 1947)
• ‘Quality of life is an individual’s perception of their
position in life in the context of the culture and
value systems in which they live and in relation to
their goals, expectations, standards and concerns.’
(WHOQOL Group, 1993)
• ‘Quality of life refers to patients’ appraisal of and
satisfaction with their current level of functioning
as compared to what they perceive to be
ideal.’(Cella and Tulsky, 1990)
• ‘Health-related quality of life is the value assigned
to duration of life as modified by the impairment,
functional states, perceptions and social opportunities
that are influenced by disease, injury,
treatment or policy.’ (Patrick and Erickson, 1993a)
• ‘Health-related quality of life refers to the level of
well-being and satisfaction associated with an
individual’s life and how this is affected by disease,
accidents and treatments from the patient’s point
of view.’ (Lovatt, 1992)
• ‘Quality of life is enhanced when the distance
between the individual’s attained and desired goals
is less.’ (Bergner, 1989)
• ‘Quality of life measures the difference, or the gap,
at a particular period of time, between the hopes
and expectations of the individual and that
individual’s experiences (Calman, 1984)
TABLE 1 Alternative perspectives underlying competing definitions of QoL in health care
Perspective Illustration
theoretical justification. None has commanded
greater attention than others.
There is therefore an enormous array of concepts
and definitions. Farquhar (1994, 1995) reviewed
the range of definitions of QoL in the field of
health and developed a typology. She distinguished
‘global definitions’ which express QoL in general
terms such as degree of satisfaction with life,
‘component definitions’ that break down QoL
into specific parts or dimensions, such as health,
life satisfaction and psychological well-being; and
‘focused definitions’ that emphasise only one or
two of the range of possible component parts
of life.
Schipper and colleagues (1996) assess the array
of different perspectives that inform definitions of
the term QoL in medical research and distinguish
five different concepts or emphases (Table 1).
They suggest that the following simple definition
captures much that is important across the five
different perspectives:
‘“Quality of life” in clinical medicine represents the
functional effect of an illness and its consequent
therapy upon a patient, as perceived by the patient’
(Schipper et al., 1996:16).
Such a definition makes a very important point
very simply with its emphasis upon the perception
of the patient. In view of the competing array of
such definitions, it would not be productive to
attempt to devise a more convincing or more
authoritative version. The result of any such
exercise would add another competing definition
to the abundance of already existing attempts. In
any case, it is our view that very substantial progress
may be made in the assessment of patient-based
outcome measures without imposing a (somewhat
The psychological view The patient’s perceptions of the impact of disease; for example, how symptoms are
experienced and labelled
The utility view The values attached to health states; the trade-offs individuals make between survival
against QoL
The community centered view The extent to which illness impacts on the individual’s relations to a community in
terms of employment, home making etc.
Reintegration into normal life The extent to which, following illness, the individual can resume normal life in terms
of self care, social activities etc.
The gap between expectations The more the patient is able to realise his or her expectations, the higher the QoL
and achievements
Adapted from Schipper et al. (1996)