Generic measures of QOL are used either alone or in combination with a condition-specific instrument. The choice of the type of measure clearly depends on the aim(s) of the study. The findings of our review indicate that a measure seems to exist for every disease. The challenge is to find instruments that can be widely used but have good psychometric properties for every health condition. The generic measures used in the included studies are well known and widely used and have been well validated across cultures.

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Quantitative measurement

Such divergences between the perceptions of those in a given health state and the perceptions of outside observers highlight the limitations of basing assessments purely on observers’ assessments. The main purpose of the health care system is to increase the well-being of those it treats. This can be achieved only if patient views are incorporated into treatment evaluations, thereby ensuring that health and medical care are fully evidence-based. The evaluation of methodological and conceptual quality or rigor according to the criteria of Gill and Feinstein 5, 8 (Table 5) revealed that 22 (13%) of the 163 studies provided a definition of the concept QOL (criterion 1). In 57 of the papers (35%), the investigators stated the domains they measured as part of QOL (criterion 2).

A Review of Utility Assessments in Quality of Life

Utility measures move the measurement of quality of life from rankings to judgments of worth and value. This extension of the field of study is controversial; most particularly, the role of utility analysis in quality-of-life research is hotly contested. To choose measures for assessing quality of life, researchers need to address seven issues, briefly reviewed below. Quality of life (QoL) is a concept which aims to capture the well-being, whether of a population or individual, regarding both positive and negative elements within the entirety of their existence at a specific point in time. Only one study in the review had a mixed-methods design, and only one was purely qualitative.

Disease-Specific Versus Global Assessments

The application of theoretical thinking leads to hypothesis generation, which makes research cumulative instead of atomistic. However, theoretical thinking needs to be interwoven in all stages of research. Its absence might engender a static concept of QOL by continuing to test the same parameters. Both qualitative and theoretical approaches to QOL are needed to open up the concept for discussion and change.

The resulting questionnaire is designed to be completed by either physicians or patients. We found no reports of uses of the instrument by investigators other than Selby and his colleagues. Padilla’s Quality of Life Index focused on physical conditions, activities, and attitudes of the patients.

Recent Activity

We used the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement) checklist to ensure rigor in conducting and the reporting of this systematic review 7. The checklist comprises 27 items including those deemed essential for transparent reporting of systematic reviews. To evaluate the conceptual and methodological rigor, we used the same ten predefined criteria developed by Gill and Feinstein 5 and refined by Moons et al. 8.

Mixed methods involve the collection and analysis of both quantitative quality of life definition and qualitative data 11. Traditionally, QOL research has been quantitative and there are few qualitative studies, although during the past years, an increasing number of qualitative QOL studies have added an important dimension to QOL research 12. However, because of the few qualitative studies and the limited search (1 week), we have not been able to identify whether the number of qualitative studies has increased in recent years. Studies of QOL have been conducted in all parts of the world, but the USA has the most published articles, followed by China. Several European countries follow; and if taken as a whole, Europe has produced more studies than the USA. These trends suggest that QOL research is being conducted mainly in developed countries.

1. The reader may wish to refer to these sources for detailed discussions of the theory and methods of utility analysis.
2. When the data were factor analyzed, Schipper et al. (1984) found that the mean factor scores for four patient groups decreased with the extent of disease.
3. In the event of any inconsistency between the English and the translated version, then the original English versions (in the Publications section below) shall be the binding and authentic versions.
4. Please note that these translations were not created by the World Health Organization (WHO).
5. Using 100 patients in a second study, the correlations were higher (0.96) (Grieco and Long 1984).

The coefficient assumes that the correlations in the matrix are all positive, because they represent the same dimension. Although researchers and policymakers tend to make much of the distinction between objective and subjective measures, both are probably necessary when assessing quality of life, and both require investigations into their reliability and validity. It is perhaps surprising that the objective measures often are not as well standardized as the subjective measures; objectivity does not automatically mean that measures are reliable and valid. Objective measures are based on variables that can be observed and recorded by various testing procedures and assessors. Measures of disease activity, remission of symptoms, presence of side effects, changes in functional capacity, ability to carry out usual activities, and family and social activities are phenomena that can be observed and recorded.