This article proposes contemporary best-practice recommendations for stated preference (SP) studies used to inform decision making, grounded in the accumulated body of peer-reviewed literature. These recommendations consider the use of SP methods to estimate both use and non-use (passive-use) values, and cover the broad SP domain, including contingent valuation and discrete choice experiments. We focus on applications to public goods in the context of the environment and human health but also consider ways in which the proposed recommendations might apply to other common areas of application. The recommendations recognize that SP results may be used and reused (benefit transfers) by governmental agencies and nongovernmental organizations, and that all such applications must be considered. The intended result is a set of guidelines for SP studies that is more comprehensive than that of the original National Oceanic and Atmospheric Administration (NOAA) Blue Ribbon Panel on contingent valuation, is more germane to contemporary applications, and reflects the two decades of research since that time. We also distinguish between practices for which accumulated research is sufficient to support recommendations and those for which greater uncertainty remains. The goal of this article is to raise the quality of SP studies used to support decision making and promote research that will further enhance the practice of these studies worldwide.

An amperometric biosensor for l-glutamic acid (Glu) was constructed by the adsorption and dip coating of l-glutamate oxidase (GluOx, 200 U ml 21 phosphate buffer, pH 7.4) onto 60-mm radius Teflon-coated Pt wire (1 mm exposed length). The enzyme was then trapped on the surface by electropolymerisation of o-phenylenediamine that also served to block electroactive interference. This procedure afforded electrodes with similar substrate sensitivity compared with the classical approach of immobilising enzyme from a solution of monomer, and represents an approximately 10 000-fold increase in the yield of biosensors from a batch of enzyme. A number of strategies were examined to enhance the sensitivity and selectivity of the Pt/PPD/GluOx sensors operating at 0.7 V versus SCE. Pre-coating the Pt with lipid and incorporation of the protein bovine serum albumin into the polymer matrix were found to improve the performance of the electrode. The sensors had a fast response time, high sensitivity to Glu, with an LOD of about 0.3 mmol l 21 , and possessed selectivity characteristics suggesting that monitoring Glu in biological tissues in vivo may be feasible.

This paper considers the application of discrete choice experiments for eliciting preferences in the delivery of health care. Drawing upon the results from a recently completed systematic review, the paper summarises the application of this technique in health care. It then presents a case study applying the technique to rheumatology outpatient clinics. 200 patients were questioned about the importance of six attributes: staV seen (junior doctor or specialist nurse); time in waiting area; continuity of contact with same staV; provision of a phone-in/advice service; length of consultation; and change in pain levels. The systematic review indicated that discrete choice experiments have been applied to a wide number of areas and a number of methodological issues have been addressed. Consistent with this literature, the case study found evidence of both rationality and theoretical validity of responses. The approach was used to establish the relative importance of diVerent attributes, how individuals trade between these attributes, and overall benefit scores for diVerent clinic configurations. The value of attributes was estimated in terms of time, and this was converted to a monetary measure using the value of waiting time for public transport. Discrete choice experiments represent a potentially useful instrument for eliciting preferences. Future methodological work should explore issues related to the experimental design of the study, methods of data collection and analysis, and satisfaction with the economic axioms of the instrument. Collaborative work with psychologists and qualitative researchers will prove useful in this research agenda. Keywords: discrete choice experiments; patient preference; decision making; patient-caregiver communication Recent years have seen an increased use of discrete choice experiments (DCEs; also known as conjoint analysis) as a technique for eliciting preferences. This paper considers what we know to date about the application of DCEs in health and identifies important areas for future research. The technique is described and its use in health economics is considered. The results from a recently completed systematic review of the technique are summarised and a case study from an outpatient rheumatology clinic is presented which demonstrates both the standard approach to conducting a DCE and its potential uses. Methodological questions that need to be addressed are discussed. Discrete choice experimentsDiscrete choice experiments are based on the premise that, firstly, any good or service can be described by its characteristics (or attributes) and, secondly, the extent to which an individual values a good or service depends upon the nature and levels of these characteristics. The technique involves presenting individuals with choices of scenarios described in terms of characteristics and associated levels. For each choice they are asked to choose their preferred scenario. Response data are modelled within a benefit (or satisfaction) function which provides information on wh...

This study developed a preference-based utility measure (Glaucoma Utility Index) using the DCE approach. The index, estimated on the basis of 286 respondents, demonstrated both theoretical and convergent validity with other generic health outcome measures and measures of glaucoma severity. Further research investigating preferences by clinically defined glaucoma health status is indicated. Methodological research should focus on alternative methods of scaling for use within a generic Quality Adjusted Life Year framework.

This study presents the first comparison of willingness to pay estimates derived from the payment card (PC) contingent valuation and discrete choice experiment (DCE) methods. A within-sample experiment was used to elicit women's preferences for Chlamydia screening. The willingness to pay estimate derived from the DCE was larger than that derived from the PC. To investigate why the willingness to pay estimates were different, a range of validity tests were conducted. Both methods produced theoretically valid results, and there was no difference in the reported difficulty of completing the tasks. Evidence of a prominence effect was found in the PC responses. Responses to the DCE satisfied tests of non-satiation. Responses to both methods were compared with revealed preference data. There were significant differences between stated screening intention in both methods and actual screening uptake. Future work should address the external validity of stated preference methods.