Own-price and cross-price elasticities of demand for cigarettes and waterpipe tobacco in three Eastern Mediterranean countries: a volumetric choice experiment.

BACKGROUND: Waterpipe tobacco smoking rates in the Eastern Mediterranean region are among the highest worldwide, yet little evidence exists on its economics. Estimates of demand elasticities for tobacco products are largely limited to cigarettes. This study aimed to estimate own-price and cross-price elasticities of demand for cigarettes and waterpipe tobacco products in Lebanon, Jordan and Palestine. METHODS: A volumetric choice experiment was conducted using nationally representative household surveys. The choice experiment elicited respondents' stated purchases of eight cigarette and waterpipe tobacco product varieties by hypothetically varying prices. Data were analysed using zero-inflated Poisson models that yielded demand elasticity estimates of cigarette and waterpipe tobacco consumption. RESULTS: The study included 1680 participants in Lebanon (50% female), 1925 in Jordan (44.6% female) and 1679 in Palestine (50% female). We found the demand for premium cigarettes to be price elastic (range, -1.0 to -1.2) across all three countries, whereas the demand for discount cigarettes was less elastic than premium cigarettes in Lebanon (-0.6) and Jordan (-0.7) and more elastic in Palestine (-1.2). The demand for premium waterpipe tobacco was highly elastic in Lebanon (-1.9), moderately elastic in Jordan (-0.6) and inelastic in Palestine (0.2). The cross-price elasticity between cigarettes and waterpipe tobacco was near zero, suggesting that the two products are not considered to be close substitutes by consumers. CONCLUSIONS: These results serve as a strong evidence base for developing and implementing fiscal policies for tobacco control in the Eastern Mediterranean region that address cigarettes and waterpipe tobacco products.

Analysis of on-pack messages for e-liquids: a discrete choice study.

BACKGROUND: Policymakers wishing to encourage smokers unable to quit to switch to using electronic nicotine delivery systems (ENDS) also need to consider how to deter ENDS use among non-smokers. We examined whether reduced-risk messages could increase ENDS' appeal among smokers and if increased-risk messages could decrease appeal among susceptible non-smokers, occasional and former smokers. METHODOLOGY: An online discrete choice experiment tested three attributes: information message, nicotine content (0 mg or 3 mg) and flavour (tobacco, menthol or fruit). The sample comprised 352 current smokers, 118 occasional and former smokers, and 216 ENDS-susceptible never smokers. Smokers viewed reduced-risk messages that encouraged switching to ENDS, while other groups viewed increased-risk messages that discouraged ENDS use. All groups saw a typical addiction warning. We analysed the data by estimating multinomial logit regression and adjusted latent class analysis models. RESULTS: Relative to no message, reduced risk-messages increased the appeal of ENDS uptake among one class of smokers (33.5%) but decreased appeal among other smokers. However, among all smokers, reduced-risk messages increased preference more than a dissuasive addiction warning. By contrast, among occasional or former smokers, and susceptible non-smokers, all information messages discouraging ENDS use, including an addiction warning, decreased preference relative to no message. CONCLUSIONS: On-pack relative-risk messages about ENDS could make transition more attractive to smokers while increased-risk messages could deter ENDS uptake among susceptible non-smokers, occasional and former smokers. Communicating diverse messages via discrete channels could recognise heterogeneity among and between smokers and non-smokers.

Who should get the scarce ICU bed? The US public's view on triage in the time of COVID-19.

OBJECTIVE: To determine the relative importance members of the US public place on different patient attributes in triage decisions about who should receive the last available intensive care unit (ICU) bed. METHODS: A discrete choice experiment was conducted with a nationally representative sample of 2000 respondents from the YouGov internet panel of US households. Respondents chose which of three hypothetical patients with COVID-19 should receive an ICU bed if only one were available. The three patients differed in age, gender, Alzheimer's-like disability and probability of survival if the patient received the ICU bed. An experimental design varied the values of the four attributes of the three hypothetical patients with COVID-19 that a respondent saw in four choice tasks. RESULTS: The most important patient attribute to respondents was the probability the patient survives COVID-19 if they get the ICU bed (OR CI: 4.41 to 6.91). There was heterogeneity among different age groups of respondents about how much age of the patient mattered. Respondents under 30 years of age were more likely to choose young patients and old patients, and less likely to select patients aged 40-60 years old. For respondents in the age group 30-49 years old, as the age of the patient declined, their preference for saving the patient declined modestly in a linear fashion. CONCLUSIONS: Respondents favoured giving the last ICU bed available to the patient with the highest probability of surviving COVID-19. Public opinion suggests a simple guideline for physician choices based on likelihood of survival as opposed to the number of life-years saved. There was heterogeneity among respondents of different age groups for allocating the last ICU bed, as well as to the importance of the patient having an Alzheimer's-like disability (where religion of the respondent is important) and the gender of the patient (where the gender and racial identity are important).

Assessing cigarette packaging and labelling policy effects on early adolescents: results from a discrete choice experiment.

INTRODUCTION: Cigarette packaging is a primary channel for tobacco advertising, particularly in countries where traditional channels are restricted. The current study evaluated the independent and interactive effects of cigarette packaging and health warning label (HWL) characteristics on perceived appeal of cigarette brands for early adolescents in Mexico. METHODS: A discrete choice experiment (DCE) was conducted with early adolescents, aged 12-14 years (n=4251). The DCE involved a 3×25 design with six attributes: brand (Marlboro, Pall Mall, Camel), tobacco flavour (regular, menthol), flavour capsule (none, 1 or 2 capsules), presence of descriptive terms, branding (vs plain packaging), HWL size (30%, 75%) and HWL content (emphysema vs mouth cancer). Participants viewed eight sets of three cigarette packs and selected a pack in each set that: (1) is most/least attractive, (2) they are most/least interested in trying or (3) is most/least harmful, with a no difference option. RESULTS: Participants perceived packs as less attractive, less interesting to try and more harmful if they had plain packaging or had larger HWLs, with the effect being most pronounced when plain packaging is combined with larger HWLs. For attractiveness, plain packaging had the biggest influence on choice (43%), followed by HWL size (19%). Interest in trying was most influenced by brand name (34%), followed by plain packaging (29%). Perceived harm was most influenced by brand name (30%), followed by HWL size (29%). CONCLUSION: Increasing the size of HWLs and implementing plain packaging appear to reduce the appeal of cigarettes to early adolescents. Countries should adopt these policies to minimise the impact of tobacco marketing.

Young adult susceptible non-smokers' and smokers' responses to capsule cigarettes.

BACKGROUND: Flavour capsule cigarette variants (FCVs), which allow users to customise their smoking experience and reduce the harshness of smoking, have captured an increasing share of many markets. We examined tobacco companies' argument that such product innovations aim simply to shift market share, by estimating smokers' and susceptible non-smokers' responses to FCVs. METHODS: We conducted an online survey of 425 smokers (daily and non-daily), susceptible non-smokers (n=224) and former smokers (n=166) aged between 18 and 25. Restrpondents completed a choice experiment, a behavioural probability measure and a perception task. We analysed the choice data using a conditional logistic regression and a rank-ordered logistic regression, and the probability and perception data using t-tests and descriptive statistics. RESULTS: Non-smokers preferred an FCV relative to an unflavoured cigarette, whereas the opposite was the case for smokers. Susceptible non-smokers and former smokers were more likely to try a fruit flavoured FCV than an unflavoured stick, while daily smokers were more likely than non-daily smokers to do the same. Susceptible non-smokers, former smokers and non-daily smokers also had more positive perceptions of FCVs relative to unflavoured sticks than did daily smokers. CONCLUSIONS: FCVs appeal more to non-smokers than to smokers, and more to non-daily smokers than to daily smokers. They thus appear likely to recruit non-smokers and potentially increase overall smoking prevalence. Policy responses include ensuring standardised packaging legislation disallows FCVs by specifically regulating the appearance and design of tobacco products, or introducing bespoke regulation that addresses the threat posed by FCVs.

Estimating the effects of novel on-pack warnings on young adult smokers and susceptible non-smokers.

BACKGROUND: On-pack tobacco warnings can deter smoking initiation and provide powerful cessation cues. However, these warnings typically feature graphic health images, which many young adults dismiss as irrelevant. We estimated responses to more diverse warnings and examined how these performed relative to each other. METHODS: We conducted a behavioural likelihood experiment and a choice modelling experiment in which 474 smokers and 476 susceptible non-smokers aged between 16 and 30 years evaluated 12 warnings featuring health, social, financial and cosmetic themes. The choice data were analysed by estimating Sequential-Best-Worst Choice and Scale-Adjusted Latent Class Models. RESULTS: Smokers found all test warnings aversive, particularly warnings featuring the effect of smoking on vulnerable third parties, including babies and animals, and showing a dying smoker. Susceptible non-smokers found graphic health warnings and a warning that combined graphic health with loss of physical attractiveness, significantly more aversive than other images tested. CONCLUSIONS: Illustrating the harms smoking causes to vulnerable groups may reduce the temporal distance and perceived control over smoking that young adults use to rationalise health warnings. Introducing more diverse warnings could recognise heterogeneity within smoker and susceptible non-smoker populations, and complement warnings featuring long-term health harms.

Evaluation of strategies to communicate harmful and potentially harmful constituent (HPHC) information through cigarette package inserts: a discrete choice experiment.

BACKGROUND: The US Food and Drug Administration (FDA) has regulatory authority to use inserts to communicate with consumers about harmful and potentially harmful constituents (HPHCs) in tobacco products; however, little is known about the most effective manner for presenting HPHC information. METHODS: In a discrete choice experiment, participants evaluated eight choice sets, each of which showed two cigarette packages from four different brands and tar levels (high vs low), accompanied by an insert that included between-subject manipulations (ie, listing of HPHCs vs grouping by disease outcome and numeric values ascribed to HPHCs vs no numbers) and within-subject manipulations (ie, 1 of 4 warning topics; statement linking an HPHC with disease vs statement with no HPHC link). For each choice set, participants were asked: (1) which package is more harmful and (2) which motivates them to not smoke; each with a 'no difference' option. Alternative-specific logit models regressed choice on attribute levels. RESULTS: 1212 participants were recruited from an online consumer panel (725 18-29-year-old smokers and susceptible non-smokers and 487 30-64-year-old smokers). Participants were more likely to endorse high-tar products as more harmful than low-tar products, with a greater effect when numeric HPHC information was present. Compared with a simple warning statement, the statement linking HPHCs with disease encouraged quit motivation. CONCLUSIONS: Numeric HPHC information on inserts appears to produce misunderstandings that some cigarettes are less harmful than others. Furthermore, brief narratives that link HPHCs to smoking-related disease may promote cessation versus communications that do not explicitly link HPHCs to disease.

Dissuasive cigarette sticks: the next step in standardised ('plain') packaging?

BACKGROUND: Standardised (or 'plain') packaging has reduced the appeal of smoking by removing imagery that smokers use to affiliate themselves with the brand they smoke. We examined whether changing the appearance of cigarette sticks could further denormalise smoking and enhance the negative impact of standardised packaging. METHODS: We conducted an online study of 313 New Zealand smokers who comprised a Best-Worst Choice experiment and a rating task. The Best-Worst experiment used a 2×3×3×6 orthogonal design to test the following attributes: on-pack warning message, branding level, warning size and stick appearance. RESULTS: We identified three segments whose members' choice patterns were strongly influenced by the stick design, warning theme and size, and warning theme, respectively. Each of the dissuasive sticks tested was less preferred and rated as less appealing than the most common stick in use; a 'minutes of life lost' stick was the most aversive of the stimuli tested. CONCLUSIONS: Dissuasive sticks could enhance the effect of standardised packaging, particularly among older smokers who are often more heavily addicted and resistant to change. Countries introducing standardised packaging legislation should take the opportunity to denormalise the appearance of cigarette sticks, in addition to removing external tobacco branding from packs and increasing the warning size.

A comparison of on-pack Quitline information formats.

BACKGROUND: Although tobacco packages have evolved to feature health warnings and, in Australia, dissuasive colours, the format of on-pack cessation information has not changed. We compared how alternative Quitline information formats affected smokers' perceptions and choice behaviours, and their likelihood of seeking cessation support. METHODS: We conducted an online study comprising a choice experiment using a two (number of panels) by three (panel position: above, middle, below) plus control (current format) design, and a between-subjects comparison of a two-panel format and the control. The sample comprised 608 New Zealand smokers. RESULTS: Relative to the current format, respondents regarded each test format as more effective in communicating cessation information (p<0.0001), particularly the two-panel formats. Respondents found the two-panel format tested via paired comparisons significantly easier to read, more visually salient and more likely than the control to encourage them and other smokers to consider quitting (all p<0.0001). Heat map comparisons showed that the Quitline number and affirming message were significantly more salient in the test format than in the current format (p<0.0001), although the headline and warning explanation were more salient in the control. CONCLUSIONS: Reformatting Quitline information could improve its visual salience and readability and capitalise on the dissonance that pictorial warning labels and plain packaging create. Enhancing stimuli that may prompt smokers to try and quit, affirming their decision to do so and prompting the use of cessation support could increase the number and success of quit attempts.

Effects of brand variants on smokers' choice behaviours and risk perceptions.

BACKGROUND: Australian tobacco companies have introduced evocative variant names that could re-create the aspirational connotations plain packaging aims to remove. To inform future regulation, we explored how brand descriptors affected smokers' responses to plain packs featuring different variant name combinations. METHODS: An online survey of 254 daily smokers or social smokers aged between 18 and 34 used a within-subjects best-worst experiment to estimate the relative effects of variant names. A 2×4×4×4 design contained four attributes: quality (premium or none), taste (smooth, fine, rich or none) connotation (classic, midnight, infinite or none) and colour (red, blue, white or none). In a between-subjects component, respondents evaluated one of two alternative packs according to its perceived harm and ease of quitting. RESULTS: The most important variant attribute was connotation, followed by taste, colour and quality; within these attributes, the most attractive descriptors were 'classic' and 'smooth'. We identified four distinct segments that differed significantly in their sociodemographic attributes and variant preferences, although not in their perceptions of the harm or quitting ease associated with two different variants. CONCLUSIONS: Some descriptors significantly enhance the appeal of tobacco products among different groups of smokers and may undermine plain packaging's dissuasive intent. Policymakers should explicitly regulate variant names to avoid the 'poetry on a package' evident in Australia. Options include disallowing new descriptors, limiting the number of descriptors permitted or banning descriptors altogether.

Estimating the 'consumer surplus' for branded versus standardised tobacco packaging.

BACKGROUND: Tobacco companies question whether standardised (or 'plain') packaging will change smokers' behaviour. We addressed this question by estimating how standardised packaging compared to a proven tobacco control intervention, price increases through excise taxes, thus providing a quantitative measure of standardised packaging's likely effect. METHODS: We conducted an online study of 311 New Zealand smokers aged 18 years and above that comprised a willingness-to-pay task comparing a branded and a standardised pack at four different price levels, and a choice experiment. The latter used an alternative-specific design, where the alternatives were a branded pack or a standardised pack, with warning theme and price varied for each pack. RESULTS: Respondents had higher purchase likelihoods for the branded pack (with a 30% warning) than the standardised pack (with a 75% warning) at each price level tested, and, on average, were willing to pay approximately 5% more for a branded pack. The choice experiment produced a very similar estimate of 'consumer surplus' for a branded pack. However, the size of the 'consumer surplus' varied between warning themes and by respondents' demographic characteristics. CONCLUSIONS: These two experiments suggest standardised packaging and larger warning labels could have a similar overall effect on adult New Zealand smokers as a 5% tobacco price increase. The findings provide further evidence for the efficacy of standardised packaging, which focuses primarily on reducing youth initiation, and suggest this measure will also bring notable benefits to adult smokers.

The development of ORACLe: a measure of an organisation's capacity to engage in evidence-informed health policy.

BACKGROUND: Evidence-informed policymaking is more likely if organisations have cultures that promote research use and invest in resources that facilitate staff engagement with research. Measures of organisations' research use culture and capacity are needed to assess current capacity, identify opportunities for improvement, and examine the impact of capacity-building interventions. The aim of the current study was to develop a comprehensive system to measure and score organisations' capacity to engage with and use research in policymaking, which we entitled ORACLe (Organisational Research Access, Culture, and Leadership). METHOD: We used a multifaceted approach to develop ORACLe. Firstly, we reviewed the available literature to identify key domains of organisational tools and systems that may facilitate research use by staff. We interviewed senior health policymakers to verify the relevance and applicability of these domains. This information was used to generate an interview schedule that focused on seven key domains of organisational capacity. The interview was pilot-tested within four Australian policy agencies. A discrete choice experiment (DCE) was then undertaken using an expert sample to establish the relative importance of these domains. This data was used to produce a scoring system for ORACLe. RESULTS: The ORACLe interview was developed, comprised of 23 questions addressing seven domains of organisational capacity and tools that support research use, including (1) documented processes for policymaking; (2) leadership training; (3) staff training; (4) research resources (e.g. database access); and systems to (5) generate new research, (6) undertake evaluations, and (7) strengthen relationships with researchers. From the DCE data, a conditional logit model was estimated to calculate total scores that took into account the relative importance of the seven domains. The model indicated that our expert sample placed the greatest importance on domains (2), (3) and (4). CONCLUSION: We utilised qualitative and quantitative methods to develop a system to assess and score organisations' capacity to engage with and apply research to policy. Our measure assesses a broad range of capacity domains and identifies the relative importance of these capacities. ORACLe data can be used by organisations keen to increase their use of evidence to identify areas for further development.

Using conjoint analysis to develop a system of scoring policymakers' use of research in policy and program development.

BACKGROUND: The importance of utilising the best available research evidence in the development of health policies, services, and programs is increasingly recognised, yet few standardised systems for quantifying policymakers' research use are available. We developed a comprehensive measurement and scoring tool that assesses four domains of research use (i.e. instrumental, conceptual, tactical, and imposed). The scoring tool breaks down each domain into its key subactions like a checklist. Our aim was to develop a tool that assigned appropriate scores to each subaction based on its relative importance to undertaking evidence-informed health policymaking. In order to establish the relative importance of each research use subaction and generate this scoring system, we conducted conjoint analysis with a sample of knowledge translation experts. METHODS: Fifty-four experts were recruited to undertake four choice surveys. Respondents were shown combinations of research use subactions called profiles, and rated on a 1 to 9 scale whether each profile represented a limited (1-3), moderate (4-6), or extensive (7-9) example of research use. Generalised Estimating Equations were used to analyse respondents' choice data, which calculated a utility coefficient for each subaction. A large utility coefficient indicated that a subaction was particularly influential in guiding experts' ratings of extensive research use. RESULTS: Utility coefficients were calculated for each subaction, which became the points assigned to the subactions in the scoring system. The following subactions yielded the largest utilities and were regarded as the most important components of each research use domain: using research to directly influence the core of the policy decision; using research to inform alternative perspectives to deal with the policy issue; using research to persuade targeted stakeholders to support a predetermined decision; and using research because it was a mandated requirement by the policymaker's organisation. CONCLUSIONS: We have generated an empirically derived and context-sensitive means of measuring and scoring the extent to which policymakers used research to inform the development of a policy document. The scoring system can be used by organisations to not only quantify the extent of their research use, but also to provide them with insights into potential strategies to improve subsequent research use.

Using conjoint analysis to develop a system to score research engagement actions by health decision makers.

BACKGROUND: Effective use of research to inform policymaking can be strengthened by policymakers undertaking various research engagement actions (e.g., accessing, appraising, and applying research). Consequently, we developed a thorough measurement and scoring tool to assess whether and how policymakers undertook research engagement actions in the development of a policy document. This scoring tool breaks down each research engagement action into its key 'subactions' like a checklist. The primary aim was to develop the scoring tool further so that it assigned appropriate scores to each subaction based on its effectiveness for achieving evidence-informed policymaking. To establish the relative effectiveness of these subactions, we conducted a conjoint analysis, which was used to elicit the opinions and preferences of knowledge translation experts. METHOD: Fifty-four knowledge translation experts were recruited to undertake six choice surveys. Respondents were exposed to combinations of research engagement subactions called 'profiles', and rated on a 1-9 scale whether each profile represented a limited (1-3), moderate (4-6), or extensive (7-9) example of each research engagement action. Generalised estimating equations were used to analyse respondents' choice data, where a utility coefficient was calculated for each subaction. A large utility coefficient indicates that a subaction was influential in guiding experts' ratings of extensive engagement with research. RESULTS: The calculated utilities were used as the points assigned to the subactions in the scoring system. The following subactions yielded the largest utilities and were regarded as the most important components of engaging with research: searching academic literature databases, obtaining systematic reviews and peer-reviewed research, appraising relevance by verifying its applicability to the policy context, appraising quality by evaluating the validity of the method and conclusions, engaging in thorough collaborations with researchers, and undertaking formal research projects to inform the policy in question. CONCLUSIONS: We have generated an empirically-derived and context-sensitive method of measuring and scoring the extent to which policymakers engaged with research to inform policy development. The scoring system can be used by organisations to quantify staff research engagement actions and thus provide them with insights into what types of training, systems, and tools might improve their staff's research use capacity.

Effects of dissuasive packaging on young adult smokers.

BACKGROUND: Tobacco industry documents illustrate how packaging promotes smoking experimentation and reinforces existing smokers' behaviour. Plain packaging reduces the perceived attractiveness of smoking and creates an opportunity to introduce larger pictorial warnings that could promote cessation-linked behaviours. However, little is known about the effects such a combined policy measure would have on smokers' behaviour. METHODS: A 3 (warning size) *4 (branding level) plus control (completely plain pack) best-worst experiment was conducted via face-to-face interviews with 292 young adult smokers from a New Zealand provincial city. The Juster Scale was also used to estimate cessation-linked behaviours among participants. RESULTS: Of the 13 options tested, respondents were significantly less likely to choose those featuring fewer branding elements or larger health warnings. Options that featured more branding elements were still preferred even when they also featured a 50% health warning, but were significantly less likely to be chosen when they featured a 75% warning. Comparison of a control pack representing the status quo (branded with 30% front of pack warning) and a plain pack (with a 75% warning) revealed the latter would be significantly more likely to elicit cessation-related behaviours. CONCLUSIONS: Plain packs that feature large graphic health warnings are significantly more likely to promote cessation among young adult smokers than fully or partially branded packs. The findings support the introduction of plain packaging and suggest use of unbranded package space to feature larger health warnings would further promote cessation.

Tasmanian landowner preferences for conservation incentive programs: a latent class approach.

An empirical model of landowners' conservation incentive program choice is developed in which information about landowners' socio-economic and property characteristics and their attitudes, is combined with incentive program attributes. In a Choice survey landowners were presented with the choice of two incentive programs modelled as 'bundles of attributes' mimicking a voluntary choice scenario. Landowner behaviour and decision and the type of conditions and regulations they preferred were analyzed. Based on choice survey data, landowner heterogeneity was accounted for using a latent class approach to estimate the preference parameters. Three latent classes of landowners with different attitudes to the role and outcome of establishing conservation reserves on private land were identified: multi-objective owners; environment owners; and production owners. Only a small proportion of landowners, mostly environment owners, would voluntarily join a program. Although compensation funding contributed to voluntary program choice for multi-objective owners and environment owners, welfare losses were around 4000 AUD per hectare, which is less than the average agricultural land value in Tasmania. Landowners for whom compensation funding contributed to voluntary program choice were also most likely to set aside land for conservation without payment. This raises the possibility that the government's compensation expenditure could potentially be either reduced or re-allocated to landowners who will not voluntarily take conservation action. Increasing participation in conservation incentive programs and minimizing the welfare losses associated with meeting conservation targets may be best achieved by offering programs that allow flexibility in terms of legal arrangements and other program attributes.

Testing and Extending Schwartz Refined Value Theory Using a Best-Worst Scaling Approach.

The theory of human values discriminated 10 basic values arrayed in a quasicircular structure. Analyses with several instruments in numerous samples supported this structure. The refined theory of human values discriminates 19 values in the same circle. Its support depends on one instrument, the revised Portrait Values Questionnaire. We introduce a forced choice method, the Best-Worst Refined Values scale (BWVr), to assess the robustness of the refined theory to method of measurement and also assess the distinctiveness and validity of a new animal welfare value. Three studies ( N = 784, 439, and 383) support the theory and the new value. Study 3 also demonstrates the convergent and discriminant validity of the 19 values by comparing the BWVr, the revised Portrait Values Questionnaire, and value-expressive behaviors and confirms the test-retest reliability of BWVr responses. These studies provide further information about the order of values in the value circle.

Estimating preferences for a dermatology consultation using Best-Worst Scaling: comparison of various methods of analysis.

BACKGROUND: Additional insights into patient preferences can be gained by supplementing discrete choice experiments with best-worst choice tasks. However, there are no empirical studies illustrating the relative advantages of the various methods of analysis within a random utility framework. METHODS: Multinomial and weighted least squares regression models were estimated for a discrete choice experiment. The discrete choice experiment incorporated a best-worst study and was conducted in a UK NHS dermatology context. Waiting time, expertise of doctor, convenience of attending and perceived thoroughness of care were varied across 16 hypothetical appointments. Sample level preferences were estimated for all models and differences between patient subgroups were investigated using covariate-adjusted multinomial logistic regression. RESULTS: A high level of agreement was observed between results from the paired model (which is theoretically consistent with the 'maxdiff' choice model) and the marginal model (which is only an approximation to it). Adjusting for covariates showed that patients who felt particularly affected by their skin condition during the previous week displayed extreme preference for short/no waiting time and were less concerned about other aspects of the appointment. Higher levels of educational attainment were associated with larger differences in utility between the levels of all attributes, although the attributes per se had the same impact upon choices as those with lower levels of attainment. The study also demonstrated the high levels of agreement between summary analyses using weighted least squares and estimates from multinomial models. CONCLUSION: Robust policy-relevant information on preferences can be obtained from discrete choice experiments incorporating best-worst questions with relatively small sample sizes. The separation of the effects due to attribute impact from the position of levels on the latent utility scale is not possible using traditional discrete choice experiments. This separation is important because health policies to change the levels of attributes in health care may be very different from those aiming to change the attribute impact per se. The good approximation of summary analyses to the multinomial model is a useful finding, because weighted least squares choice totals give better insights into the choice model and promote greater familiarity with the preference data.

Rescaling quality of life values from discrete choice experiments for use as QALYs: a cautionary tale.

BACKGROUND: Researchers are increasingly investigating the potential for ordinal tasks such as ranking and discrete choice experiments to estimate QALY health state values. However, the assumptions of random utility theory, which underpin the statistical models used to provide these estimates, have received insufficient attention. In particular, the assumptions made about the decisions between living states and the death state are not satisfied, at least for some people. Estimated values are likely to be incorrectly anchored with respect to death (zero) in such circumstances. METHODS: Data from the Investigating Choice Experiments for the preferences of older people CAPability instrument (ICECAP) valuation exercise were analysed. The values (previously anchored to the worst possible state) were rescaled using an ordinal model proposed previously to estimate QALY-like values. Bootstrapping was conducted to vary artificially the proportion of people who conformed to the conventional random utility model underpinning the analyses. RESULTS: Only 26% of respondents conformed unequivocally to the assumptions of conventional random utility theory. At least 14% of respondents unequivocally violated the assumptions. Varying the relative proportions of conforming respondents in sensitivity analyses led to large changes in the estimated QALY values, particularly for lower-valued states. As a result these values could be either positive (considered to be better than death) or negative (considered to be worse than death). CONCLUSION: Use of a statistical model such as conditional (multinomial) regression to anchor quality of life values from ordinal data to death is inappropriate in the presence of respondents who do not conform to the assumptions of conventional random utility theory. This is clearest when estimating values for that group of respondents observed in valuation samples who refuse to consider any living state to be worse than death: in such circumstances the model cannot be estimated. Only a valuation task requiring respondents to make choices in which both length and quality of life vary can produce estimates that properly reflect the preferences of all respondents.

Conducting discrete choice experiments to inform healthcare decision making: a user's guide.

Discrete choice experiments (DCEs) are regularly used in health economics to elicit preferences for healthcare products and programmes. There is growing recognition that DCEs can provide more than information on preferences and, in particular, they have the potential to contribute more directly to outcome measurement for use in economic evaluation. Almost uniquely, DCEs could potentially contribute to outcome measurement for use in both cost-benefit and cost-utility analysis. Within this expanding remit, our intention is to provide a resource for current practitioners as well as those considering undertaking a DCE, using DCE results in a policy/commercial context, or reviewing a DCE. We present the fundamental principles and theory underlying DCEs. To aid in undertaking and assessing the quality of DCEs, we discuss the process of carrying out a choice study and have developed a checklist covering conceptualizing the choice process, selecting attributes and levels, experimental design, questionnaire design, pilot testing, sampling and sample size, data collection, coding of data, econometric analysis, validity, interpretation and welfare and policy analysis. In this fast-moving area, a number of issues remain on the research frontier. We therefore outline potentially fruitful areas for future research associated both with DCEs in general, and with health applications specifically, paying attention to how the results of DCEs can be used in economic evaluation. We also discuss emerging research trends. We conclude that if appropriately designed, implemented, analysed and interpreted, DCEs offer several advantages in the health sector, the most important of which is that they provide rich data sources for economic evaluation and decision making, allowing investigation of many types of questions, some of which otherwise would be intractable analytically. Thus, they offer viable alternatives and complements to existing methods of valuation and preference elicitation.