Does the value of quality of life depend on duration?

The aims of this study are to investigate the feasibility of eliciting Time Trade Off (TTO) valuations using short durations; to determine the effect of contrasting durations on individuals’ responses to the TTO; to examine variations within and between respondents’ values with respect to duration; and to consider the insights provided by participants’ comments and explanations regarding their reaction to duration in the valuation task. 27 participants provided TTO values using short and long durations for three EQ-5D states. Feedback was sought using a series of open ended questions. Of the 81 opportunities to observe it, strict constant proportionality was satisfied twice. 11 participants had no systematic relationship between duration and value; 11 provided consistently lower valuations in long durations, while 5 had higher valuations in long durations. Comments provided by participants were consistent with the values they provided. Mean TTO values did not differ markedly between alternative durations. We conclude that it is feasible to elicit TTO values for short durations. There is considerable heterogeneity in individuals’ responses to the time frames used to elicit values. Further research is required to ensure that the values used in cost effectiveness analysis adequately represent preferences about quality and length of life

A uniform Time Trade Off method for states better and worse than dead: feasibility study of the ‘lead time’ approach

The way Time Trade Off (TTO) values are elicited for states of health considered ‘worse than being dead’ has important implications for the mean values used in economic evaluation. Conventional approaches to TTO, as used in the UK’s ‘MVH’ value set, are problematic because they require fundamentally different tradeoffs tasks for the valuation of states better and worse than dead. This study aims to refine and test the feasibility of a new approach described by Robinson and Spencer (2006), and to explore the characteristics of the valuation data it generates. The approach introduces a ‘lead time’ into the TTO, producing a uniform procedure for generating values either >0 or <0. We used this lead time TTO to value 10 moderate to severe EQ-5D states using a sample of the general public (n=109). We conclude that the approach is feasible for use in valuation studies, and appears to overcome the discontinuity in values around 0 evident in conventional methods. However, further research is required to resolve the issue of how to handle participants who ‘use up’ all lead time; to develop ways of controlling for individual time preferences; and to better understand the implications for valuations of states better than dead

Using a discrete choice experiment to estimate societal health state utility values

In this study we explore a novel application of the Discrete Choice Experiment (DCE) that resembles the Time Trade Off (TTO) task to estimate values on the health utility scale for the EQ-5D. The DCE is tested in a survey alongside the TTO in respondents largely representative of the Canadian general population. The study finds that the DCE is able to derive logical and consistent values for health states valued on the full health – dead scale. The DCE overcame some issues identified in the version of TTO currently used to value EQ-5D, notably whether to exclude respondents who fail to understand the task and incorporating values considered worse than dead without transformation. This has important implications for providing values that represent the preferences of all respondents

Stability of superfluid Fermi gases in optical lattices

Critical velocities of superfluid Fermi gases in optical lattices are theoretically investigated across the BCS-BEC crossover. We calculate the excitation spectra in the presence of a superfluid flow in one- and two-dimensional optical lattices. It is found that the spectrum of low-lying Anderson-Bogoliubov (AB) mode exhibits a roton-like structure in the short-wavelength region due to the strong charge density wave fluctuations, and with increasing the superfluid velocity one of the roton-like minima reaches zero before the single-particle spectrum does. This means that superfluid Fermi gases in optical lattices are destabilized due to spontaneous emission of the roton-like AB mode instead of due to Cooper pair breaking.Comment: 4 pages, 4 figures, conference proceeding for ISQM-TOKYO'0

Equal access for equal need: Eliciting public preferences for access to health treatment by employment status

The National Health Service in the UK is set up under the principle of “equal access for equal need”, where those with identical medical needs should be given equal priority in receiving health care. However, non-medical needs may also be relevant in health care decision-making. This paper considers how members of the general public value access to a health service given equal medical needs, where some service users have additional non-medical needs. There are three primary research questions. First, are public preferences regarding access to a health care service symmetric and inequality averse? Second, are public preferences asymmetric across different needs groups? And third, which individual characteristics of respondents are predictive of different public preferences in this domain? An online survey of the UK general public was conducted in January 2017 using binary choice questions. The hypothetical scenarios involved allocating extra resources from a social perspective, to reduce the waiting time to access a mental health service for the unemployed, for the employed, or for both groups. Based on a valid sample of 662 respondents, the study found that the three main preference categories were: inequality averse and symmetric, inequality averse and asymmetric in favour of the unemployed, and inequality seeking and asymmetric in favour of the unemployed, with the first group being the largest. Respondents’ current labour market status was found to explain their preferences so that those who were currently job-seeking were more likely to demonstrate preferences that favoured the unemployed, and those who were currently unemployed were less likely to demonstrate asymmetric preferences that favoured the employed. The implications from these findings are that health policies in the UK that support equal access for equal medical need are likely to be received most favourably, yet a non-trivial minority may support policies favouring those with other, non-medical needs