A view from the Bridge: agreement between the SF-6D utility algorithm and the Health utilities Index

BACKGROUND: The SF-6D is a new health state classification and utility scoring system based on 6 dimensions (‘6D’) of the Short Form 36, and permits a ‘‘bridging’’ transformation between SF-36 responses and utilities. The Health Utilities Index, mark 3 (HUI3) is a valid and reliable multi-attribute health utility scale that is widely used. We assessed within-subject agreement between SF-6D utilities and those from HUI3. METHODS: Patients at increased risk of sudden cardiac death and participating in a randomized trial of implantable defibrillator therapy completed both instruments at baseline. Score distributions were inspected by scatterplot and histogram and mean score differences compared by paired t-test. Pearson correlation was computed between instrument scores and also between dimension scores within instruments. Between-instrument agreement was by intra-class correlation coefficient (ICC). RESULTS: SF-6D and HUI3 forms were available from 246 patients. Mean scores for HUI3 and SF-6D were 0.61 (95% CI 0.60–0.63) and 0.58 (95% CI 0.54–0.62) respectively; a difference of 0.03 (p50.03). Score intervals for HUI3 and SF-6D were (-0.21 to 1.0) and (0.30–0.95). Correlation between the instrument scores was 0.58 (95% CI 0.48–0.68) and agreement by ICC was 0.42 (95% CI 0.31–0.52). Correlations between dimensions of SF-6D were higher than for HUI3. CONCLUSIONS: Our study casts doubt on the whether utilities and QALYs estimated via SF-6D are comparable with those from HUI3. Utility differences may be due to differences in underlying concepts of health being measured, or different measurement approaches, or both. No gold standard exists for utility measurement and the SF-6D is a valuable addition that permits SF-36 data to be transformed into utilities to estimate QALYs. The challenge is developing a better understanding as to why these classification-based utility instruments differ so markedly in their distributions and point estimates of derived utilities

Enhancing Irrigation Efficiency but Increasing Water Use: The Jevons' Paradox

In this paper we analyze the conditions under which increasing technical efficiency of water use in the agricultural sector might not reduce water demand and pressures on water ecosystems. Departing from this basic problem we discuss how policy measures performed to enhance water productivity in the agriculture might be transformed into effective alternatives to improve the conservation of water resources and then guarantee the successful implementation of the Water Framework Directive. A preference revelation model is presented in the third section of the paper and one empirical application to an irrigation district in southern Spain is used in the fourth section to discuss the effectiveness of water savings measures.Water Framework Directive, Water Economics, Agricultural Economics, Simulation Models, Preference Revelation., Resource /Energy Economics and Policy,

A framework for the selection of the right nuclear power plant

Civil nuclear reactors are used for the production of electrical energy. In the nuclear industry vendors propose several nuclear reactor designs with a size from 35–45 MWe up to 1600–1700 MWe. The choice of the right design is a multidimensional problem since a utility has to include not only financial factors as levelised cost of electricity (LCOE) and internal rate of return (IRR), but also the so called “external factors” like the required spinning reserve, the impact on local industry and the social acceptability. Therefore it is necessary to balance advantages and disadvantages of each design during the entire life cycle of the plant, usually 40–60 years. In the scientific literature there are several techniques for solving this multidimensional problem. Unfortunately it does not seem possible to apply these methodologies as they are, since the problem is too complex and it is difficult to provide consistent and trustworthy expert judgments. This paper fills the gap, proposing a two-step framework to choosing the best nuclear reactor at the pre-feasibility study phase. The paper shows in detail how to use the methodology, comparing the choice of a small-medium reactor (SMR) with a large reactor (LR), characterised, according to the International Atomic Energy Agency (2006), by an electrical output respectively lower and higher than 700 MWe

Choice Experiments in Enviromental Impact Assessment: The Toro 3 Hydroelectric Project and the Recreo Verde Tourist Center in Costa Rica

Choice experiments, a stated preference valuation method, are proposed as a tool to assign monetary values to environmental externalities during the ex-ante stages of environmental impact assessment. This case study looks at the impacts of the Costa Rican Institute of Electricity’s Toro 3 hydroelectric project and its affects on the Recreo Verde tourism center in San Carlos, Costa Rica. Compared to other valuation methods (e.g., travel cost and contingent valuation), choice experiments can create hypothetical but realistic scenarios for consumers and generate restoration alternatives for the affected good. Although they have limitations that must be taken into account in environmental impact assessments, incorporating economic parameters—especially resource constraints and tradeoffs—can substantially enrich the assessment process.stated-preference, economic valuation, choice experiments, hydropower, tourism, Costa Rica

The relative value of different QALY types

The oft-applied assumption in the use of Quality Adjusted Life Years (QALYs) in economic evaluation, that all QALYs are valued equally, has been questioned from the outset. The literature has focused on differential values of a QALY based on equity considerations such as the characteristics of the beneficiaries of the QALYs. However, a key characteristic which may affect the value of a QALY is the type of QALY itself. QALY gains can be generated purely by gains in survival, purely by improvements in quality of life, or by changes in both. Using a discrete choice experiment and a new methodological approach to the derivation of relative weights, we undertake the first direct and systematic exploration of the relative weight accorded different QALY types and do so in the presence of equity considerations; age and severity. Results provide new evidence against the normative starting point that all QALYs are valued equally.This study was funded by an Australian National Health and Medical Research Council project grant APP1047788

Consumer Heterogeneity and the Impact of Trade Liberalization: How Representative is the Representative Agent Framework?

While it is well established that across-country taste differences are associated with "home market effects", there is very limited analysis of how such preference heterogeneity impacts the aggregate volume of trade and the welfare gains from liberalization. I develop a structural model of aggregate demand featuring products with heterogeneous attributes, consumers with heterogeneous tastes for attributes, and across-country differences in the distribution of tastes. The impact of across-country taste differences depends on whether the domestic industry can adjust to the mismatch between the attribute composition of imports and the domestic distribution of tastes. For the case of a large degree of across-country taste differences, countries specialize completely and the model supports notions along the lines of Linder (1961) that taste diversity impedes the volume of trade and leads to group-specific gains from trade. In contrast, if specialization is incomplete, free firm entry implies that the relative toughness of competition across different market segments must be invariant to liberalization. It is shown that therefore, both trade volume and welfare gains are entirely unaffected by the distribution of foreign tastes and coincide with those in a representative agent framework.Intra-Industry Trade, Monopolistic Competition, Heterogeneous Agents, Industrial Structure, Firm Dynamics

Destination Choice Models for Rock Climbing in the Northeast Alps: A Latent-Class Approach Based on Intensity of Participation

Practitioners of outdoor sports, such as rock-climbers, are likely to exhibit preference heterogeneity that depends on the ‘keenness’ with which such sports are practiced. Such an intuition is born out in at least one study using latent class discrete choice modelling (Provencher et al. 2002). Preference heterogeneity has a reflection on the population’s structure of recreational values assigned to rock-climbing destinations, to their attributes and ultimately to land management policies addressing such attributes. In this study such hypothesis is tested on a panel of destination choices by a sample of rock-climbers members of the Veneto Chapter of the Italian Alpine Club. Preliminary estimates of latent-class (finite-mixing) specifications provided evidence that intensity of participation explained heterogeneity in taste. This motivated our splitting of the sample in a ‘high’ and a ‘low’ intensity of participation sub-samples, each of which is in turn analysed for the presence of endogenous preference classes using latent-class random utility based approaches. We find evidence in support of the hypothesis that there are at least four statistically well-defined classes in each sub-sample, thereby revealing a considerable richness in the structure of preference, which would otherwise be unobservable in more conventional approaches. From the model estimates, we first focus on the derivation of posterior individual specific welfare measures for some key destination attributes, and then for a welfare neutral land management policy. One emerging feature is the strong evidence of multi-modal distribution of values, a feature that is more difficult to capture when preference heterogeneity is modelled by other means. The results also show how the proposed policy is progressive in terms of benefit distribution in the sample, and that the distribution of individual welfare changes shows markedly different patterns between high and low demand sub-samples.Travel cost model, Preference heterogeneity, Non-market valuation, Random utility model, Latent class analysis, Rock-climbing, Destination choice modelling

What are GPs' preferences for financial and non-financial incentives in cancer screening? Evidence for breast, cervical, and colorectal cancers

We benefited for this research from grants provided by the French National Institute for Cancer (INCa) (INCA_7014). We would like to thank Dr Diane Skatun, Mary Kilonzo, and the three anonymous reviewers for their useful comments on the paper.Peer reviewedPostprin