Would you rather be ill now, or later?

The Time Tradeoff (TTO) method is used to calculate the quality adjustment of the Quality Adjusted Life Year, and is therefore an important element in the calculation of the benefits of medical interventions. New specifications of TTO, known as ‘lead time’ TTO and ‘lag time’ TTO, have been developed to overcome methodological issues of the ‘classic’ TTO. In the lead time TTO, ill-health is explicitly placed in the future, after a period of good health, while in lag time TTO a health state starts immediately and is followed by a ‘lag time’ of good health. In this study, we take advantage of these timing properties of lead and lag time TTO. In particular, we use data from a previous study that employed lead and lag time TTO to estimate their implied discounting parameters. We show that individuals prefer being ill later, rather than now, with larger per-period discount rates for longer durations of the health states

The way that you do it? An elaborate test of procedural invariance of TTO, using a choice-based design

The time tradeoff (TTO) method is often used to derive Quality-Adjusted Life Year health state valuations. An important problem with this method is that results have been found to be responsive to the procedure used to elicit preferences. In particular, fixing the duration in the health state to be valued and inferring the duration in full health that renders an individual indifferent, causes valuations to be higher than when the duration in full health is fixed and the duration in the health state to be valued is elicited. This paper presents a new test of procedural invariance for a broad range of time horizons, while using a choice-based design and adjusting for discounting. As one of the known problems with the conventional procedure is the violation of constant proportional tradeoffs (CPTO), we also investigate CPTO for the alternative TTO procedure. Our findings concerning procedural invariance are rather supportive for the TTO procedure. We find no violations of procedural invariance except for the shortest gauge duration. The results for CPTO are more troublesome: TTO scores depend on gauge duration, reinforcing the evidence reported when using the conventional procedure

Eliciting risk preferences that predict risky health behaviour: A comparison of two approaches

Information on attitudes to risk could increase understanding of and explain risky health behaviors. We investigate two approaches to eliciting risk preferences in the health domain, a novel “indirect” lottery elicitation approach with health states as outcomes and a “direct” approach where respondents are asked directly about their willingness to take risks. We compare the ability of the two approaches to predict health-related risky behaviors in a general adult population. We also investigate a potential framing effect in the indirect lottery elicitation approach. We find that risk preferences elicited using the direct approach can better predict health-related risky behavior than those elicited using the indirect approach. Moreover, a seemingly innocuous change to the framing of the lottery question results in significantly different risk preference estimates, and conflicting conclusions about the ability of the indicators to predict risky health behaviors

On the (not so) constant proportional trade-off in TTO

Abstract. Purpose: The linear and power QALY models require that people in Time Trade-off (TTO) exercises sacrifice the same proportion of lifetime to obtain a health improvement, irrespective of the absolute amount. However, evidence on these constant proportional trade-offs (CPTOs) is mixed, indicating that these versions of the QALY model do not represent preferences. Still, it may be the case that a more general version of the QALY model represents preferences. This version has the property that people want to sacrifice the same proportion of utilities of lifetime for a health improvement, irrespective of the amount of this lifetime. Methods: We use a new method to correct TTO scores for utility of life duration and test whether decision makers trade off utility of duration and quality at the same rate irrespective of duration. Results: We find a robust violation of CPTO for both uncorrected and corrected TTO scores. Remarkably, we find higher values for longer durations, contrary to most previous studies. This represents the only study correcting for utility of life duration to find such a violation. Conclusions: It seems that the trade-off of life years is indeed not so constantly proportional and, therefore, that health state valuations depend on durations

Time to tweak the TTO. But how?

This paper examines the effect different specifications of the Time Tradeoff (TTO) task have on health state values. The new lead time TTO is compared to an equally viable method called lag time TTO, both in two time frames. We test whether the two methods yield comparable health state values and whether the relative importance of dimensions of health is similarly stable between TTO specifications. The tasks were applied online and compared to results from a study with identical TTO specifications but with a different mode of administration. Lag time TTO produced lower values than lead time TTO and the difference was larger in the longer time frame. The relative importance of different dimensions of health was affected by the duration of the health state. Generally, the lead time TTO performed in group sessions gave more favorable results than the online exercise based on feasibility and data quality

Time to tweak the TTO. But how?

This paper examines the effect different specifications of the Time Tradeoff (TTO) task have on health state values. The new lead time TTO is compared to an equally viable method called lag time TTO, both in two time frames. We test whether the two methods yield comparable health state values and whether the relative importance of dimensions of health is similarly stable between TTO specifications. The tasks were applied online and compared to results from a study with identical TTO specifications but with a different mode of administration. Lag time TTO produced lower values than lead time TTO and the difference was larger in the longer time frame. The relative importance of different dimensions of health was affected by the duration of the health state. Generally, the lead time TTO performed in group sessions gave more favorable results than the online exercise based on feasibility and data quality

Discounting in Economic Evaluations

Appropriate discounting rules in economic evaluations have received considerable attention in the literature and in national guidelines for economic evaluations. Rightfully so, as discounting can be quite influential on the outcomes of economic evaluations. The most prominent controversies regarding discounting involve the basis for and height of the discount rate, whether costs and effects should be discounted at the same rate, and whether discount rates should decline or stay constant over time. Moreover, the choice for discount rules depends on the decision context one adopts as the most relevant. In this article, we review these issues and debates, and describe and discuss the current discounting recommendations of the countries publishing their national guidelines. We finish the article by proposing a research agenda

The effects of lead time and visual aids in TTO valuation: a study of the EQ-VT framework

__Abstract__ __Background__ The effect of lead time in time trade-off (TTO) valuation is not well understood. The purpose of this study was to investigate the effects on health-state valuation of the length of lead time and the way the lead-time TTO task is displayed visually. __Methods__ Using two general population samples, we compared three lead-time TTO variants: 10 years of lead time in full health preceding 5 years of unhealthy time (standard); 5 years of lead time preceding 5 years of unhealthy time (experimental); and 10 years of lead time and 5 years of unhealthy time, presented with a visual aid to highlight the point where the lead time ends (experimental). Participants were randomized to receive one of the lead-time variants, as administered by a computer software program. __Results__ Health-state values generated by TTO valuation tasks using a longer lead time were slightly lower than those generated by tasks using a shorter lead time. When lead time and unhealthy time were presented with visual aids highlighting the difference between the lead time and unhealthy time, respondents spent more time considering health states with a value close to 0. __Conclusions__ Different lead-time time trade-off variants should be carefully studied in order to achieve the best measurement of health-state values using this new method

Your money and your life: risk attitudes over gains and losses

Prospect theory is the most influential descriptive alternative to the orthodox model of rational choice under risk and uncertainty, in terms of empirical analyses of some of its principal parameters and as a consideration in behavioural public policy. Yet the most distinctive implication of the theory – a fourfold predicted pattern of risk attitudes called the reflection effect – has been infrequently studied and with mixed results over money outcomes, and has never been completely tested over health outcomes. This article reports tests of reflection over money and health outcomes defined by life years gained from treatment. With open valuation exercises, the results suggest qualified support for the reflection effect over money outcomes and strong support over health outcomes. However, in pairwise choice questions, reflection was substantially ameliorated over life years, remaining significant only for treatments that offered short additional durations of life