Eliciting willingness to pay in obstetrics: comparing a direct and an indirect valuation method for complex health outcomes

The use of machine learning to understand the role of visual attention in multi-attribute choice

Whether eye movements (as a measure of visual attention) contribute to the understanding of how multi-attribute decisions are made, is still a matter of debate. In this study, we show how machine learning methods can be used to separate the effects of the information presented, eye movement patterns, and attention to specific information. We also show how to deal with data from a relatively small sample of participants, often found in eye tracking studies that require in-lab testing. We make use of a dataset of 30 females who decided whether or not to accept screening for Chlamydia in 21 different scenarios. For this dataset, we find that eye movements did not add to the prediction of choice beyond the information presented to participants. Future studies should determine whether the same conclusion holds for other eye tracking datasets.

Maximum Acceptable Risk Estimation Based on a Discrete Choice Experiment and a Probabilistic Threshold Technique

OBJECTIVE

We aimed to empirically compare maximum acceptable risk results estimated using both a discrete choice experiment (DCE) and a probabilistic threshold technique (PTT).

METHODS

Members of the UK general public (n = 982) completed an online survey including a DCE and a PTT (in random order) measuring their preferences for preventative treatment for rheumatoid arthritis. For the DCE, a Bayesian D-efficient design consisting of four blocks of 15 choice tasks was constructed including six attributes with varying levels. The PTT used identical risk and benefit attributes. For the DCE, a panel mixed-logit model was conducted, both mean and individual estimates were used to calculate maximum acceptable risk. For the PTT, interval regression was used to calculate maximum acceptable risk. Perceived complexity of the choice tasks and preference heterogeneity were investigated for both methods.

RESULTS

Maximum acceptable risk confidence intervals of both methods overlapped for serious infection and serious side effects but not for mild side effects (maximum acceptable risk was 32.7 percent-points lower in the PTT). Although, both DCE and PTT tasks overall were considered easy or very easy to understand and answer, significantly more respondents rated the DCE choice tasks as easier to understand compared with those who rated the PTT as easier (7-percentage point difference; p < 0.05).

CONCLUSIONS

Maximum acceptable risk estimate confidence intervals based on a DCE and a PTT overlapped for two out of the three included risk attributes. More respondents rated the DCE as easier to understand. This may suggest that the DCE is better suited in studies estimating maximum acceptable risk for multiple risk attributes of differing severity, while the PTT may be better suited when measuring heterogeneity in maximum acceptable risk estimates or when investigating one or more serious adverse events.

Informing decision makers about public preferences for different modalities of cancer treatment in the Rhône-Alps region in France

BACKGROUND

Alternative options to hospital care like home care or local health centers (LHCs) are being advocated. However, no study has measured citizens' preferences (who will finance these services via taxation) for these options.

OBJECTIVES

We measured (i) citizens' preferences for these services, that is, respondents stated where they would like to get the treatment; (ii) the strength of their preference.

METHODS

A computerized survey composed of (i) a decision aid to inform respondents about the three options; (ii) three scenarios, from light-to-heavy care, that respondents should rank from the most to the least preferred option of care. (iii) a contingent valuation survey (CVS) to assess how much respondents were willing to pay for their preferred option (except for hospital care if chosen, because it is the default option and free). (iv) a socio-demographic questionnaire.

RESULTS

Data were collected from a representative sample of citizens living in the Rhône-Alps Region (n = 800). The heavier the care was, the more respondents preferred hospital care. Willingness to pay for additional taxation per household/month varied from €13.9 for light care in LHC to €19.1 for heavy home care. The small number of protesting respondents and outliers, and the close correlation between preferences, income, and WTP supports the validity of the CVS.

CONCLUSION

In France, for cancer, not all citizens would prefer to be treated at home rather than in a hospital. Only less than a quarter would prefer LHC. These results show the mismatch between public health policies and the citizens' preferences.

Test-Retest Reliability of EQ-5D-Y-3L Best-Worst Scaling Choices of Adolescents and Adults

BACKGROUND

There is an increasing interest to obtain adolescents' own health state valuation preferences and to understand how these differ from adult preferences for the same health state. An important question in health state valuation is whether adolescents can report preferences reliably, yet research remains limited.

OBJECTIVE

This study aims to investigate the test-retest reliability of best-worst scaling (BWS) to elicit adolescent preferences compared with adults.

METHODS

Identical BWS tasks designed to value 3-level version of EQ-5D-Y health states were administered online in samples of 1000 adolescents (aged 11-17 years) and 1006 adults in Spain. The valuation survey was repeated approximately 3 days later. We calculated (1) simple percentage agreement and (2) kappa statistic as measures of test-retest reliability. We also compared BWS marginal frequencies and relative attribute importance between baseline and follow-up to explore similarities in the obtained preferences.

RESULTS

We found that both adolescents and adults were able to report their preferences with moderate reliability (kappa: 0.46 for adolescents, 0.46 for adults) for best choices and fair to moderate reliability (kappa: 0.39 for adolescents, 0.41 for adults) for worst choices. No notable difference was observed across years of child age. Higher consistency was observed for best choices than worst in some dimensions for both populations. No significant differences were found in the relative attribute importance between baseline and follow-up in both populations.

CONCLUSION

Our results suggest that BWS is a reliable elicitation technique to value 3-level version of EQ-5D-Y health states in both adolescents and adults.

Willingness-to-pay for cancer treatment and outcome: a systematic review

BACKGROUND

Understanding patient preferences in cancer management is essential for shared decision-making. Patient or societal willingness-to-pay (WTP) for desired outcomes in cancer management represents their preferences and values of these outcomes.

OBJECTIVE

The aim of this systematic review is to critically evaluate how current literature has addressed WTP in relation to cancer treatment and achievement of outcomes.

METHODS

Seven databases were searched from inception until 2 March 2021 to include studies with primary data of WTP values for cancer treatments or achievement of outcomes that were elicited using stated preference methods.

RESULTS

Fifty-four studies were included in this review. All studies were published after year 2000 and more than 90% of the studies were conducted in high-income countries. Sample size of the studies ranged from 35 to 2040, with patient being the most studied population. There was a near even distribution between studies using contingent valuation and discrete choice experiment. Based on the included studies, the highest WTP values were for a quality-adjusted life year (QALY) ($11,498-$589,822), followed by 1-year survival ($3-$198,576), quality of life (QoL) improvement ($5531-$139,499), and pain reduction ($79-$94,662). Current empirical evidence suggested that improvement in QoL and pain reduction had comparable weights to survival in cancer management.

CONCLUSION

This systematic review provides a summary on stated preference studies that elicited patient preferences via WTP and summarised their respective values. Respondents in this review had comparable WTP for 1-year survival and QoL, suggesting that improvement in QoL should be emphasised together with survival in cancer management.

Understanding community health worker incentive preferences in Uganda using a discrete choice experiment

Background

Community health workers (CHWs) play a critical role in supporting health systems, and in improving the availability and accessibility to health care. However, CHW programs globally continue to face challenges with poor performance and high levels of CHW attrition. CHW programs are often underfunded and poorly planned, which can lead to loss of motivation by CHWs. The study aims to determine preferences of CHWs for job incentives with the goal of furthering their motivation and success.

Methods

Relevant incentive attributes were identified through focus group discussions and in-depth interviews with CHWs, non-governmental organization CHWs, CHW supervisors, and policy-level stakeholders. Based on seven attributes (eg, training, workload, stipend) we developed a discrete choice experiment (DCE) that was administered to 399 CHWs across eight districts in Uganda. We used conditional and mixed multinomial logit models to estimate the utility of each job attribute. We calculated the marginal willingness to accept as the trade-off the CHWs were willing to make for a change in salary.

Results

CHWs preferred higher salaries, though salary was not the most important attribute. There was a preference for reliable transportation, such as a bicycle (β = 1.86, 95% CI = 1.06, 2.67), motorcycle (β = 1.81, 95% CI = 1.27, 2.34) or transport allowance (β = 1.37, 95% CI = 0.65, 2.10) to no transport. Formal identification including identity badges (β = 1.61, 95% CI = 0.72, 2.49), branded uniforms (β = 1.04, 95% CI = 0.45, 1.63) and protective branded gear (β = 0.76, 95% CI = 0.32, 1.21) were preferred compared to no identification. CHWs also preferred more regular refresher trainings, the use of mobile phones as job-aids and a lesser workload. The relative importance estimates suggested that transport was the most important attribute, followed by identification, refresher training, salary, workload, recognition, and availability of tools. CHWs were willing to accept a decrease in salary of USH 31 240 (US$8.5) for identity badges, and a decrease of USH85 300 (US$23) for branded uniforms to no identification.

Conclusions

This study utilized CHW and policymaker perspectives to identify realistic and pragmatic incentives to improve CHW working conditions, which is instrumental in improving their retention. Non-monetary incentives (eg, identification, transportation) are crucial motivators for CHWs and should be considered as part of the compensation package to facilitate improved performance of CHW programs.

Integrating supply and demand in cultural ecosystem services assessment: a case study of Cuihua Mountain (China)

As human demand for ecosystem services (ES) continues to increase, ES assessments have gradually become a popular research topic. Among ES, cultural ES (CES) are often overlooked and are difficult to measure during research because of their invisibility. However, the importance and usage of CES increase with supply and demand, which is key to linking the ecosystem with human well-being. This paper quantitatively evaluates various cultural services and generates corresponding Value Index (VI) maps; it then further explores the current dynamics of supply and demand. We selected Cuihua Mountain (CM) as the study area, and we applied the Social Values of Ecosystem Services (SolVES) model to evaluate CES and generated five specific VI maps to indicate the potential service stock (ES capacity). The actual supply (ES supply) is based on the attribute of the visibility of observation points on leisure routes, and the visitors (ES demand) to the service come from socio-economic data as a measure of the rates of access to entertainment venues. The supply and demand relationship (ES budget) solves the significant problems related to the oversupply and shortage of ES in space. The results showed that the CES supply power of CM is greater than the actual demand; thus, there is great potential for future development. This study also provided a reference and guidance for environmental decision-making and development in other regions.

Understanding Midwives' Preferences for Providing Information About Newborn Bloodspot Screening

Background: Understanding preferences for information provision in the context of health care service provision is challenging because of the number of potential attributes that may influence preferences. This study aimed to identify midwives’ preferences for the process and outcomes of information provision in an expanded national newborn bloodspot screening program. Design: A sample of practicing midwives completed a hybrid-stated preference survey including a conjoint analysis (CA) and discrete choice experiment to quantify preferences for the types of, and way in which, information should be provided in a newborn bloodspot screening program. Six conjoint analysis questions captured the impact of different types of information on parents’ ability to make a decision, and 10 discrete choice experiment questions identified preferences for four process attributes (including parents’ ability to make a decision). Results: Midwives employed by the UK National Health Service (n = 134) completed the survey. All types of information content were perceived to improve parents’ ability to make a decision except for the possibility of false-positive results. Late pregnancy was seen to be the best time to provide information, followed by day 3 postbirth. Information before 20 weeks of pregnancy was viewed as reducing parents’ ability to make a decision. Midwives preferred information to be provided by an individual discussion and did not think parents should receive information on the Internet. Conclusion: A hybrid stated preference survey design identified that a wide variety of information should be provided to maximize parents’ ability to make a decision ideally provided late in pregnancy or on day 3 postbirth.

A framework to address key issues of neonatal service configuration in England: the NeoNet multimethods study

Background

There is an inherent tension in neonatal services between the efficiency and specialised care that comes with centralisation and the provision of local services with associated ease of access and community benefits. This study builds on previous work in South West England to address these issues at a national scale.

Objectives

(1) To develop an analytical framework to address key issues of neonatal service configuration in England, (2) to investigate visualisation tools to facilitate the communication of findings to stakeholder groups and (3) to assess parental preferences in relation to service configuration alternatives.

Main outcome measures

The ability to meet nurse staffing guidelines, volumes of units, costs, mortality, number and distance of transfers, travel distances and travel times for parents.

Design

Descriptive statistics, location analysis, mathematical modelling, discrete event simulation and economic analysis were used. Qualitative methods were used to interview policy-makers and parents. A parent advisory group supported the study.

Setting

NHS neonatal services across England.

Data

Neonatal care data were sourced from the National Neonatal Research Database. Information on neonatal units was drawn from the National Neonatal Audit Programme. Geographic and demographic data were sourced from the Office for National Statistics. Travel time data were retrieved via a geographic information system. Birth data were sourced from Hospital Episode Statistics. Parental cost data were collected via a survey.

Results

Location analysis shows that to achieve 100% of births in units with ≥ 6000 births per year, the number of birth centres would need to be reduced from 161 to approximately 72, with more parents travelling > 30 minutes. The maximum number of neonatal intensive care units (NICUs) needed to achieve 100% of very low-birthweight infants attending high-volume units is 36 with existing NICUs, or 48 if NICUs are located wherever there is currently a neonatal unit of any level. Simulation modelling further demonstrated the workforce implications of different configurations. Mortality modelling shows that the birth of very preterm infants in high-volume hospitals reduces mortality (a conservative estimate of a 1.2-percentage-point lower risk) relative to these births in other hospitals. It is currently not possible to estimate the impact of mortality for infants transferred into NICUs. Cost modelling shows that the mean length of stay following a birth in a high-volume hospital is 9 days longer and the mean cost is £5715 more than for a birth in another neonatal unit. In addition, the incremental cost per neonatal life saved is £460,887, which is comparable to other similar life-saving interventions. The analysis of parent costs identified unpaid leave entitlement, food, travel, accommodation, baby care and parking as key factors. The qualitative study suggested that central concerns were the health of the baby and mother, communication by medical teams and support for families.

Limitations

The following factors could not be modelled because of a paucity of data – morbidity outcomes, the impact of transfers and the maternity/neonatal service interface.

Conclusions

An evidence-based framework was developed to inform the configuration of neonatal services and model system performance from the perspectives of both service providers and parents.

Future work

To extend the modelling to encompass the interface between maternity and neonatal services.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

Minimally-invasive dental anesthesia: Patients' preferences and analysis of the willingness-to-pay index

AIM

The aim of the present prospective study was to evaluate the impact of a computer-controlled anesthesia on patients' comfort and to investigate, through the willingness-to-pay (WTP) index, and patients' acceptance of this new technology.

METHODS

Fifty patients undergoing a class I or II restorative procedure were enrolled. A computer-controlled device for anesthetic delivery was utilized, and a questionnaire on the level of discomfort and WTP was given to all patients.

RESULTS

A total of 86% of participants declared less discomfort than that perceived during their last traditional procedure for pain control; 58% of patients were willing to pay an additional fee for a modern anesthesia technique, with a median WTP value of 20$.

CONCLUSIONS

Computer-controlled systems for local anesthesia represent a relevant tool for reducing patients' discomfort during dental treatment. The WTP index helps to quantify its relevance.

Modelling Nonlinearities and Reference Dependence in General Practitioners' Income Preferences

This paper tests for the existence of nonlinearity and reference dependence in income preferences for general practitioners. Confirming the theory of reference dependent utility within the context of a discrete choice experiment, we find that losses loom larger than gains in income for Norwegian general practitioners, i.e. they value losses from their current income level around three times higher than the equivalent gains. Our results are validated by comparison with equivalent contingent valuation values for marginal willingness to pay and marginal willingness to accept compensation for changes in job characteristics. Physicians' income preferences determine the effectiveness of 'pay for performance' and other incentive schemes. Our results may explain the relative ineffectiveness of financial incentive schemes that rely on increasing physicians' incomes. Copyright © 2015 John Wiley & Sons, Ltd.

Expectant Mother’s Preferences for Services in Public Hospitals of Tamil Nadu, India

Substantial programmatic efforts have been undertaken to improve the access to maternal care services in the public health system of India, yet the service users are often regarded as passive recipients. Limited research is available on the preferences of service users on what they regard the greatest issues in service delivery. A hospital-based discrete choice experiment (DCE) has been conducted in the public health facilities of Tamil Nadu, a southern state of India. This study uses a sample of 261 women who came for antenatal check-ups across six different public hospitals in Tamil Nadu. The DCE technique, which is rooted in random utility theory (RUT), and conditional logit model have been used to analyze the relative importance of health service attributes. The result showed that regular ward visits by specialist doctors like obstetricians and gynaecologists (O&G) and paediatricians were the most preferred attribute of the maternal care service. Expectant mothers are willing to wait the maximum and are prepared to tolerate health service characteristics in public hospitals, such as poor patient amenities, poor staff attitude and lack of privacy maintained during physical examination, provided specialist doctors are available in the hospitals.

Preferences for a third-trimester ultrasound scan in a low-risk obstetric population: a discrete choice experiment

OBJECTIVE

Establish maternal preferences for a third-trimester ultrasound scan in a healthy, low-risk pregnant population.

DESIGN

Cross-sectional study incorporating a discrete choice experiment.

SETTING

A large, urban maternity hospital in Northern Ireland.

PARTICIPANTS

One hundred and forty-six women in their second trimester of pregnancy.

METHODS

A discrete choice experiment was designed to elicit preferences for four attributes of a third-trimester ultrasound scan: health-care professional conducting the scan, detection rate for abnormal foetal growth, provision of non-medical information, cost. Additional data collected included age, marital status, socio-economic status, obstetric history, pregnancy-specific stress levels, perceived health and whether pregnancy was planned. Analysis was undertaken using a mixed logit model with interaction effects.

MAIN OUTCOME MEASURES

Women's preferences for, and trade-offs between, the attributes of a hypothetical scan and indirect willingness-to-pay estimates.

RESULTS

Women had significant positive preference for higher rate of detection, lower cost and provision of non-medical information, with no significant value placed on scan operator. Interaction effects revealed subgroups that valued the scan most: women experiencing their first pregnancy, women reporting higher levels of stress, an adverse obstetric history and older women.

CONCLUSIONS

Women were able to trade on aspects of care and place relative importance on clinical, non-clinical outcomes and processes of service delivery, thus highlighting the potential of using health utilities in the development of services from a clinical, economic and social perspective. Specifically, maternal preferences exhibited provide valuable information for designing a randomized trial of effectiveness and insight for clinical and policy decision makers to inform woman-centred care.

Empirical Testing of the External Validity of a Discrete Choice Experiment to Determine Preferred Treatment Option: The Case of Sleep Apnea

There is an increasing use of the discrete choice experiment (DCE) method in health care to estimate preferences of individuals and the public for different services. Despite this increasing use, there are few studies that investigate the validity of the DCE in health. This study investigates the external validity of DCE by comparing the predicted treatment choices from the DCE to the actual treatment choices made by the same respondents using a decision board (DB) approach. The sample includes 140 patients who came for a sleep apnea routine visit in a hospital setting. Each respondent answered 10 DCE tasks and 1 DB task. The preferences were estimated with a generalized multinomial logit model and the predicted and actual treatment choices were compared both at the sample and individual levels. The results raise questions about the external validity of DCE in health. At the sample level, the comparison showed large but not significant differences between the two methods. This can be explained in part by the aggregation process that obscures variability in the individuals' preferences. At the individual level, the comparison showed that the two methods led to significantly different patterns of choices.

Willingness to pay to avoid health risks from road-traffic-related air pollution and noise across five countries

We conducted a multi-country study to estimate the perceived economic values of traffic-related air pollution and noise health risks within the framework of a large European project. We used contingent valuation as a method to assess the willingness-to-pay (WTP) for both types of pollutants simultaneously. We asked respondents how much they would be willing to pay annually to avoid certain health risks from specific pollutants. Three sets of vignettes with different levels of information were provided prior to the WTP questions. These vignettes described qualitative general health risks, a quantitative single health risk related to a pollutant, and a quantitative scenario of combined health risks related to a pollutant. The mean WTP estimates to avoid road-traffic air pollution effects for the three vignettes were: €130 per person per year (pp/y) for general health risks, €80 pp/y for a half year shorter in life expectancy, and €330 pp/y to a 50% decrease in road-traffic air pollution. Their medians were €40 pp/y, €10 pp/y and €50 pp/y, respectively. The mean WTP estimates to avoid road-traffic noise effects for the three vignettes were: €90 pp/y for general health risks, €100 pp/y for a 13% increase in severe annoyance, and €320 pp/y for a combined-risk scenario related to an increase of a noise level from 50 dB to 65 dB. Their medians were €20 pp/y, €20 pp/y and €50 pp/y, respectively. Risk perceptions and attitudes as well as environmental and pollutant concerns significantly affected WTP estimates. The observed differences in crude WTP estimates between countries changed considerably when perception-related variables were included in the WTP regression models. For this reason, great care should be taken when performing benefit transfer from studies in one country to another.

Discrete choice experiments in health economics: a review of the literature

BACKGROUND

Discrete choice experiments (DCEs) are increasingly used in health economics to address a wide range of health policy-related concerns.

OBJECTIVE

Broadly adopting the methodology of an earlier systematic review of health-related DCEs, which covered the period 2001-2008, we report whether earlier trends continued during 2009-2012.

METHODS

This paper systematically reviews health-related DCEs published between 2009 and 2012, using the same database as the earlier published review (PubMed) to obtain citations, and the same range of search terms.

RESULTS

A total of 179 health-related DCEs for 2009-2012 met the inclusion criteria for the review. We found a continuing trend towards conducting DCEs across a broader range of countries. However, the trend towards including fewer attributes was reversed, whilst the trend towards interview-based DCEs reversed because of increased computer administration. The trend towards using more flexible econometric models, including mixed logit and latent class, has also continued. Reporting of monetary values has fallen compared with earlier periods, but the proportion of studies estimating trade-offs between health outcomes and experience factors, or valuing outcomes in terms of utility scores, has increased, although use of odds ratios and probabilities has declined. The reassuring trend towards the use of more flexible and appropriate DCE designs and econometric methods has been reinforced by the increased use of qualitative methods to inform DCE processes and results. However, qualitative research methods are being used less often to inform attribute selection, which may make DCEs more susceptible to omitted variable bias if the decision framework is not known prior to the research project.

CONCLUSIONS

The use of DCEs in healthcare continues to grow dramatically, as does the scope of applications across an expanding range of countries. There is increasing evidence that more sophisticated approaches to DCE design and analytical techniques are improving the quality of final outputs. That said, recent evidence that the use of qualitative methods to inform attribute selection has declined is of concern.

Parents' preferences for seasonal influenza vaccine for their children in Japan

In Japan, trivalent inactivated influenza vaccine is the only approved influenza vaccine. It is typically administrated by hypodermic injection, and children under 13 years of age are recommended to be vaccinated two times during each winter season. Live-attenuated influenza vaccine (LAIV) is administered by a thimerosal-free nasal spray. If LAIV is approved in the future in Japan, parents will have an alternative type of influenza vaccine for their children. This study investigated parents' preference for the type of seasonal influenza vaccine for their children if alternatives are available. The marginal willingness to pay for vaccine benefits was also evaluated. We conducted a discrete choice experiment, a quantitative approach that is often used in healthcare studies, in January 2013. Respondents were recruited from a registered online survey panel, and parents with at least one child under 13 years of age were offered questionnaires. This study showed that for seasonal influenza vaccines for their children, parents are more likely to value safety, including thimerosal-free vaccines and those with a lower risk of adverse events, instead of avoiding the momentary pain from an injection. If LAIV is released in Japan, the fact that it is thimerosal-free could be an advantage. However, for parents to choose LAIV, they would need to accept the slightly higher risk of minor adverse events from LAIV.

Multi-country willingness to pay study on road-traffic environmental health effects: are people willing and able to provide a number?

BACKGROUND

The health impacts from traffic-related pollutants bring costs to society, which are often not reflected in market prices for transportation. We set out to simultaneously assess the willingness-to-pay (WTP) for traffic-related air pollution and noise effect on health, using a single measurement instrument and approach. We investigated the proportion and determinants of "protest vote/PV responses (people who were against valuing their health in terms of money)" and "don't know"/DK answers, and explored the effect of DK on the WTP distributions.

METHODS

Within the framework of the EU-funded project INTARESE, we asked over 5,200 respondents in five European countries to state their WTP to avoid health effects from road traffic-related air pollution and noise in an open-ended web-based questionnaire. Determinants of PV and DK were studied by logistic regression using variables concerning socio-demographics, income, health and environmental concern, and risk perception.

RESULTS

About 10% of the respondents indicated a PV response and between 47-56% of respondents gave DK responses. About one-third of PV respondents thought that costs should be included in transportation prices, i.e. the polluter should pay. Logistic regression analyses showed associations of PV and DK with several factors. In addition to social-demographic, economic and health factors known to affect WTP, environmental concern, awareness of health effects, respondent's ability to relax in polluted places, and their view on the government's role to reduce pollution and on policy to improve wellbeing, also affected the PV and DK response. An exploratory weighting and imputation exercise did not show substantial effects of DK on the WTP distribution.

CONCLUSIONS

With a proportion of about 50%, DK answers may be a more relevant issue affecting WTP than PV's. The likelihood to give PV and DK response were influenced by socio-demographic, economic and health factors, as well as environmental concerns and appreciation of environmental conditions and policies. In contested policy issues where actual policy may be based on WTP studies, PV and DK answers may indeed affect the outcome of the WTP study. PV and DK answers and their determinants therefore deserve further study in CV studies on environmental health effects.

Prosthetic restoration in the single-tooth gap: patient preferences and analysis of the WTP index

OBJECTIVE

The objective of this study was to evaluate the preference of a patients' population, according to the index of willingness to pay (WTP), against two treatments to restore a single-tooth gap: the implant-supported crown (ISC) and the 3-unit fixed partial denture prosthesis (FPDP) on natural teeth.

MATERIALS AND METHODS

Willingness to pay values were recorded on 107 subjects by asking the WTP from a starting bid of €2000 modifiable through monetary increases or decreases (€100). Data were collected through an individually delivered questionnaire. The characteristics of the population and choices made, the median values and WTP associations with socio-demographic parameters (Mann-Whitney and Kruskal-Wallis tests), correlations between variables (chi-square test in contingency tables) and significant parameters for predicting WTP values obtained in a multiple linear regression model were revealed.

RESULTS

The 64% of patients expressed a preference for ISC, while the remaining 36% of the population chose the FPDP. The current therapeutic choice and those carried out in the past were generally in agreement (>70% of cases, P = 0.0001); a relationship was discovered between the anterior and posterior area to the same method of rehabilitation (101 of 107 cases, 94.4%). The WTP median values for ISC were of €3000 and of €2500 in the anterior and posterior areas, respectively. The smallest amount of money has been allocated for FPDP in posterior region (median of €1500). The "importance of oral care" for the patient was a significant predictor, in the regression model analysis, for the estimation of both anterior (P = 0.0003) and posterior (P < 0.0001) WTP values. The "previous therapy" variable reached and was just close to significance in anterior (P = 0.0367) and posterior (P = 0.0511) analyses, respectively.

CONCLUSIONS

Within the limitations of this study, most of the population (64%) surveyed indicated the ISC as a therapeutic solution for the replacement of a single missing tooth, showing a higher WTP index in the anterior area. Among investigated socio-demographic variables, the importance assigned by the patient to oral care appeared to influence WTP values of the rehabilitation, regardless the location of the single gap in the mouth.

Obstetrical outcome valuations by patients, professionals, and laypersons: differences within and between groups using three valuation methods

Background

Decision-making can be based on treatment preferences of the patient, the doctor, or by guidelines based on lay people's preferences. We compared valuations assigned by three groups: patients, obstetrical care professionals, and laypersons, for health states involving both mother and (unborn) child. Our aim was to compare the valuations of different groups using different valuation methods and complex obstetric health outcome vignettes that involve both maternal and neonatal outcomes.

Methods

Patients (n = 24), professionals (n = 30), and laypersons (n = 27) valued the vignettes using three valuation methods: visual analogue scale (VAS), time trade-off (TTO), and discrete choice experimentation (DCE). Each vignette covered five health attributes: maternal health ante partum, time between diagnosis and delivery, process of delivery, maternal outcome, and neonatal outcome. We used feasibility questionnaires, Generalization theory, test-retest reliability and within-group reliability to compare the valuation patterns between groups and methods. We assessed relative weights from each valuation method to test for consistency across groups.

Results

Test-retest reliability was equal across groups, but different across methods: highest for VAS (ICC = 0.61-0.73), intermediate for TTO (ICC = 0.24-0.74) and lowest for DCE (kappa = 0.15-0.37). Within-group reliability was highest in all groups with VAS (ICC = 0.70-0.73), intermediate with DCE (kappa = 0.56-0.76) and lowest with TTO (ICC = 0.20-0.66). Effects of groups were smaller than effects of methods. Differences between groups were largest for severe health states.

Conclusion

Based on our results, decision making among laypersons should use TTO or DCE; patients should use VAS or TTO.