George W. Torrance

Measurement of health state utilities for economic appraisal: A review

Health status measurement for use in economic appraisal of health care programmes is reviewed in this paper, with particular emphasis on utility measurement. A framework for economic appraisal is presented displaying the various components that must be measured, and showing how the three forms of analysis (cost-effectiveness analysis, cost-benefit analysis and cost-utility analysis) relate to the framework and to each other. One of the components in the framework is health status; it can be measured using ad hoc numeric scales, willingness to pay/receive or health state utilities. The determination of health state utilities is reviewed covering the following issues: alternative sources of utilities, health state descriptions, multi-attribute utility approach, determination of appropriate subjects, utility aggregation, and accuracy. Three measurement techniques for health state utilities are described in detail: rating scale, standard gamble, and time trade-off. The use of these methods is described for both chronic and temporary health states and for both health states considered better than death and those considered worse than death.

Multiattribute and single-attribute utility functions for the Health Utilities index mark 3 system

Background. The Health Utilities Index Mark 3 (HUI3) is a generic multiattribute preference‐based measure of health status and health‐related quality of life that is widely used as an outcome measure in clinical studies, in population health surveys, in the estimation of quality‐adjusted life years, and in economic evaluations. HUI3 consists of eight attributes (or dimensions) of health status: vision, hearing, speech, ambulation, dexterity, emotion, cognition, and pain with 5 or 6 levels per attribute, varying from highly impaired to normal. Objectives. The objectives are to present a multiattribute utility function and eight single‐attribute utility functions for the HUI3 system based on community preferences. Study Design. Two preference surveys were conducted. One, the modeling survey, collected preference scores for the estimation of the utility functions. The other, the direct survey, provided independent scores to assess the predictive validity of the utility functions. Measures. Preference measures included value scores obtained on the Feeling Thermometer and standard gamble utility scores obtained using the Chance Board. Respondents. A random sample of the general population (≥16 years of age) in Hamilton, Ontario, Canada. Results. Estimates were obtained for eight single‐attribute utility functions and an overall multiattribute utility function. The intraclass correlation coefficient between directly measured utility scores and scores generated by the multiattribute function for 73 health states was 0.88. Conclusions. The HUI3 scoring function has strong theoretical and empirical foundations. It performs well in predicting directly measured scores. The HUI3 system provides a practical way to obtain utility scores based on community preferences.

Utility approach to measuring health-related quality of life☆

Quality of life is a broad concept that incorporates all aspects of an individuals existence. Health-related quality of life is a subset relating only to the health domain of that existence. The utility approach can be used to measure a single cardinal value, usually between 0 and 1, that reflects the health-related quality of life of the individual at a particular point in time. The utility approach is founded in modern utility theory, a normative rational model of decision-making under uncertainty. The measurement techniques that have been used include standard gamble, time trade-off, and rating scales. The techniques are described in the paper and compared in terms of their acceptability to subjects, reliability, precision, validity, and ease of use. It is concluded that the utility approach is beyond the experimental stage, and is now a viable alternative for investigators to use in measuring health-related quality of life.

Multiattribute Utility Function for a Comprehensive Health Status Classification System Health Utilities Index Mark 2

The Health Utilities Index Mark 2 (HUI:2) is a generic multiattribute, preference-based system for assessing health-related quality of life. Health Utilities Index Mark 2 consists of two components: a seven-attribute health status classification system and a scoring formula. The seven attributes are sensation, mobility, emotion, cognition, self-care, pain, and fertility. A random sample of general population parents were interviewed to determine cardinal preferences for the health states in the system. The health states were defined as lasting for a 60-year lifetime, starting at age 10. Values were measured using visual analogue scaling. Utilities were measured using a standard gamble technique. A scoring formula is provided, based on a multiplicative multiattribute utility function from the responses of 194 subjects. The utility scores are death-anchored (death = 0.0) and form an interval scale. Health Utilities Index Mark 2 and its utility scores can be useful to other researchers in a wide variety of settings who wish to document health status and assign preference scores.

The Health Utilities Index (HUI®): concepts, measurement properties and applications

This is a review of the Health Utilities Index (HUI®) multi-attribute health-status classification systems, and single- and multi-attribute utility scoring systems. HUI refers to both HUI Mark 2 (HUI2) and HUI Mark 3 (HUI3) instruments. The classification systems provide compact but comprehensive frameworks within which to describe health status. The multi-attribute utility functions provide all the information required to calculate single-summary scores of health-related quality of life (HRQL) for each health state defined by the classification systems. The use of HUI in clinical studies for a wide variety of conditions in a large number of countries is illustrated. HUI provides comprehensive, reliable, responsive and valid measures of health status and HRQL for subjects in clinical studies. Utility scores of overall HRQL for patients are also used in cost-utility and cost-effectiveness analyses. Population norm data are available from numerous large general population surveys. The widespread use of HUI facilitates the interpretation of results and permits comparisons of disease and treatment outcomes, and comparisons of long-term sequelae at the local, national and international levels.

Utilities and Quality-Adjusted Life Years

Utilities and quality-adjusted life years (QALYs) are reviewed, with particular focus on their use in technology assessment. This article provides a broad overview and perspective on these two techniques and their interrelationship, with reference to other sources for details of implementation. The historical development, assumptions, strengths/weaknesses, and applications of each are summarized. Utilities are specifically designed for individual decision-making under uncertainty, but, with additional assumptions, utilities can be aggregated across individuals to provide a group utility function. QALYs are designed to aggregate in a single summary measure the total health improvement for a group of individuals, capturing improvements from impacts on both quantity of life and quality of life--with quality of life broadly defined. Utilities can be used as the quality-adjustment weights for QALYs; they are particularly appropriate for that purpose, and this combination provides a powerful and highly useful variation on cost-effectiveness analysis known as cost-utility analysis.

The utility of different health states as perceived by the general public.

A series of ‘scenarios’ describing the physical, social and emotional characteristics, limitations and duration of different health states have been successfully applied to a random sample of the general public in order to determine their social utility. The resulting mean daily health state utilities differ among disorders and vary with age, the duration of the disorder, the ‘label’ used to describe the disorder and the health status of the respondent. These health state utilities have considerable potential application in the planning and financing of health services.

The Health Utilities Index (HUI®) system for assessing health-related quality of life in clinical studies

This paper reviews the Health Utilities Index (HUI? systems as means to describe health status and obtain utility scores reflecting health-related quality of life (HRQoL). The HUI Mark 2 (HUI2) and Mark 3 (HUI3) classification and scoring systems are described. The methods used to estimate multiattribute utility functions for HUI2 and HUI3 are reviewed. The use of HUI in clinical studies for a wide variety of conditions in a large number of countries is illustrated. HUI provides a comprehensive description of the health status of subjects in clinical studies. HUI has been shown to be a reliable, responsive and valid measure in a wide variety of clinical studies. Utility scores provide an overall assessment of the HRQoL of patients. Utility scores are also useful in cost-utility analyses and related studies. General population norm data are available. The widespread use of HUI facilitates the interpretation of results and permits comparisons. HUI is a useful tool for assessing health status and HRQoL in clinical studies.

Multi-Attribute Preference Functions

SummaryMulti-attribute utility theory. an extension of conventional utility theory, can be applied to model preference scores for health slates defined by multi-attribute health status classification systems. The type of preference independence among the attributes determines the type of preference function required: additive, multiplicative or multilinear. In addition, the type of measurement instrument used determines the type of preference score obtained: value or utility.Multi-attribute utility theory has been applied to 2 recently developed multi-attribute health status classification systems the Health Utilities Index (HUI) Mark II and Mark III systems. Results are presented for the Mark system, and ongoing research is described for the Mark system. The theory is also discussed in the context of ocher well known multi-attribute systems.The HUI system is an efficient method of determining a general public-based utility score for a specified health outcome or for the health status of an individual. In clinical populations, the scores can be used 10 provide a single summary measure of health-related quality of life. In cost-utility analyses, the scores can be used as quality weights for calculating quality-adjusted life years. In general populations, the measure can be used as quality weights for determining population health expectancy.

Social preferences for health states: An empirical evaluation of three measurement techniques

Abstract Health state preferences measured on the general public provide useful information in their own right as well as being necessary data for the application of many health status index models. But, how should the preferences be measured? This paper reports the results of an empirical investigation in which three measurement techniques are applied to several samples of the general public to measure the social preferences for ten different health states. The standard gamble technique by von Neumann-Morgenstern, a time trade-off technique by the author, and a category scaling method are analyzed with respect to their feasibility, reliability, validity and comparability.