Neil Day

A comparison of the Assessment of Quality of Life (AQoL) with four other generic utility instruments

As part of the validation of the Assessment of Quality of Life (AQoL) instrument comparisons were made between five multiattribute utility (MAU) instruments, each purporting to measure health-related quality of life (HRQoL). These were the AQoL, the Canadian Health Utilities Index (HUI) 3, the Finnish 15D, the EQ-5D (formerly the EuroQoL) and the SF6D (derived from the SF-36). The paper compares absolute utility scores, instrument sensitivity, and incremental differences in measured utility between different instruments predicted by different individuals. The AQoL predicted utilities are similar to those from the HUI3 and EQ-5D. By contrast the 15D and SF6D predict systematically higher utilities, and the differences between individuals are significantly smaller. There is some evidence that the AQoL has greater sensitivity to health states than other instruments. It is concluded that at present no single MAU instrument can claim to be the ‘gold standard’, and that researchers should select an instrument sensitive to the health states they are investigating. Caution should be exercised in treating any of the instrument scores as representing a trade-off between length of life and HRQoL.

Construction of the descriptive system for the assessment of quality of life AQoL-6D utility instrument

BackgroundMulti attribute utility (MAU) instruments are used to include the health related quality of life (HRQoL) in economic evaluations of health programs. Comparative studies suggest different MAU instruments measure related but different constructs. The objective of this paper is to describe the methods employed to achieve content validity in the descriptive system of the Assessment of Quality of Life (AQoL)-6D, MAU instrument.MethodsThe AQoL program introduced the use of psychometric methods in the construction of health related MAU instruments. To develop the AQoL-6D we selected 112 items from previous research, focus groups and expert judgment and administered them to 316 members of the public and 302 hospital patients. The search for content validity across a broad spectrum of health states required both formative and reflective modelling. We employed Exploratory Factor Analysis and Structural Equation Modelling (SEM) to meet these dual requirements.Results and DiscussionThe resulting instrument employs 20 items in a multi-tier descriptive system. Latent dimension variables achieve sensitive descriptions of 6 dimensions which, in turn, combine to form a single latent QoL variable. Diagnostic statistics from the SEM analysis are exceptionally good and confirm the hypothesised structure of the model.ConclusionsThe AQoL-6D descriptive system has good psychometric properties. They imply that the instrument has achieved construct validity and provides a sensitive description of HRQoL. This means that it may be used with confidence for measuring health related quality of life and that it is a suitable basis for modelling utilities for inclusion in the economic evaluation of health programs.

Eligibility and Self-Selection: Discontinuities in Transition to Tertiary Education in Victoria.

Most studies of transition to tertiary education focus on a single outcome variable: expectations of further study, a dichotomous indicator of participation in college and university, or simply years of further education achieved. In this paper, the authors contend that a more complete analysis of the social and personal factors which determine tertiary participation can be gained by regarding transition as a series of discontinuities in the individuals educational history. If an analysis was to commence with a cohort of Year 12 students, indicators of these discontinuities could include completion of Year 12, application to a college or university, receipt of an offer, self-selection at enrolment, and delayed entry. In a recent published study of college and university applicants in Victoria, the authors used administrative and survey data to develop causal models of the decision of successful applicants to enrol either full- or part-time rather than defer or decline. In this paper the administrative data are used to specify a model which includes two transition variables. The variables identify those who received an offer, from a defined cohort of applicants, and those who subsequently took up the offer. This model enables a distinction to be made between factors which affect the students’ eligibili!y to enrol and factors that affect subsequent self-selection into tertiary education. Group and individual inequalities can therefore be assessed in terms of their total effecton transition and their separate effects on eligibility and self-selection.

Jeopardizing Validity by Mismeasurement of Quality of Life

Practitioners and policy-makers have a common interest in an instrument that will measure the value people place on different health states. For practitioners, a patient’s valuation can guide individual decisions. For senior managers and policy-makers the information can help them decide which services to provide and which technologies to install. It is therefore disappointing to encounter results, such as those from the Leung study in this issue of The Journal 1, that show 2 reputable and widely used instruments that purport to provide such information giving different results. It raises a number of questions: How can such an outcome arise? What should practitioners and policy-makers do in view of such a finding? Measuring patient quality of life (QOL) is a relatively new venture — in particular, measurement using multi-attribute utility (MAU) instruments, like those used in the Leung study. MAU are questionnaires in which response categories are scored using utility weights that purport to measure the strength of preference for a health state. In principle, the application of these weights permits comparison of dissimilar health states. A higher score for health state A versus health state B does not have clinical meaning. Rather, a higher score indicates that there is a subjective preference for health state A by the person or persons whose judgment was used to create the utility weights. MAU instruments are now widely employed in the calculation of quality-adjusted life-years (QALY) or, more correctly, preference-adjusted life-years. Used in economic evaluation studies, QALY serve to rank dissimilar services (cost utility analysis). A variant of the QALY — the disability-adjusted life-year — is used to estimate the burden of disease (for example, the recent World Health Organization Burden of Disease Study2). The field is currently dominated by a limited number of MAU instruments. … Address correspondence to N.A. Day; E-mail: neilathertonday{at}bigpond.com

Political participation and democracy in Britain: Party and values

The previous chapter looked at very broad orientations towards the political system and the degree of confidence people had in their capacity to take effective action within it. Such action is very often prompted by quite specific issues and problems which people face. The context of issues within which people participated will be the subject of chapter 11. But, occupying an intermediate position between the broadest of perceptions of the political process and the recognition of immediate issues are a number of outlooks by means of which individuals place themselves in the political spectrum. Amongst the most central of these outlooks in the modern political world tends to be the stance people take towards the political parties which play such a significant role in aggregating values. Closely linked to this sense of identification with political parties are the alignments of people on those issues which have traditionally distinguished the political left from the political right. Since the 1960s, however, new sets of issues have emerged with steadily increasing prominence which do not readily fit into the old dichotomy between left and right based, as it mainly is, on material issues. Amongst the issues of this ‘new politics’ are the environment, nuclear weapons and their potential threat to world peace and survival, and the status of women in a male-dominated society. The very emergence of these new issues carries with it some implication that old modes of participation have not handled them adequately.