Estimating a constant WTP for a QALY-a mission impossible?

A systematic review on the direct approach to elicit the demand-side cost-effectiveness threshold: Implications for low- and middle-income countries

Several literature review studies have been conducted on cost-effectiveness threshold values. However, only a few are systematic literature reviews, and most did not investigate the different methods, especially in-depth reviews of directly eliciting WTP per QALY. Our study aimed to 1) describe the different direct approach methods to elicit WTP/QALY; 2) investigate factors that contribute the most to the level of WTP/QALY value; and 3) investigate the relation between the value of WTP/QALY and GDP per capita and give some recommendations on feasible methods for eliciting WTP/QALY in low- and middle-income countries (LMICs). A systematic review concerning select studies estimating WTP/QALY from a direct approach was carried out in seven databases, with a cut off date of 03/2022. The conversion of monetary values into 2021 international dollars (i$) was performed via CPI and PPP indexes. The influential factors were evaluated with Bayesian model averaging. Criteria for recommendation for feasible methods in LMICs are made based on empirical evidence from the systematic review and given the resource limitation in LMICs. A total of 12,196 records were identified; 64 articles were included for full-text review. The WTP/QALY method and values varied widely across countries with a median WTP/QALY value of i$16,647.6 and WTP/QALY per GDP per capita of 0.53. A total of 11 factors were most influential, in which the discrete-choice experiment method had a posterior probability of 100%. Methods for deriving WTP/QALY vary largely across studies. Eleven influential factors contribute most to the level of values of WTP/QALY, in which the discrete-choice experiment method was the greatest affected. We also found that in most countries, values for WTP/QALY were below 1 x GDP per capita. Some important principles are addressed related to what LMICs may be concerned with when conducting studies to estimate WTP/QALY.

Establishing cost-effectiveness threshold in China: a community survey of willingness to pay for a healthylife year

INTRODUCTION

The willingness to pay per quality-adjusted life year gained (WTP/Q) is commonly used to determine whether an intervention is cost-effective in health technology assessment. This study aimed to evaluate the WTP/Q for different disease scenarios in a Chinese population.

METHODS

The study employed a quadruple-bounded dichotomous choice contingent valuation method to estimate the WTP/Q in the general public. The estimation was conducted across chronic, terminal and rare disease scenarios. Face-to-face interviews were conducted in a Chinese general population recruited from Jiangsu province using a convenience sampling method. Interval regression analysis was performed to determine the relationship between respondents' demographic and socioeconomic conditions and WTP/Q. Sensitivity analyses of removing protest responses and open question analyses were conducted.

RESULTS

A total of 896 individuals participated in the study. The WTP/Q thresholds were 128 000 Chinese renminbi (RMB) ($36 364) for chronic diseases, 149 500 RMB ($42 472) for rare diseases and 140 800 RMB ($40 000) for terminal diseases, equivalent to 1.76, 2.06 and 1.94 times the gross domestic product per capita in China, respectively. The starting bid value had a positive influence on participants' WTP/Q. Additionally, residing in an urban area (p<0.01), and higher household expenditure (p<0.01), educational attainment (p<0.02) and quality of life (p<0.02) were significantly associated with higher WTP/Q. Sensitivity analyses demonstrated the robustness of the results.

CONCLUSION

This study implies that tailored or varied rather than a single cost-effectiveness threshold could better reflect community preferences for the value of a healthy year. Our estimates hold significance in informing reimbursement decision-making in health technology assessment in China.

Willingness to pay for cancer prevention versus treatment in China: implications for cost-effectiveness threshold

BACKGROUND

Empirical support for the appropriate cost-effectiveness threshold (CET) in China remains sparse.

OBJECTIVE

This study aimed to estimate the willingness to pay (WTP) for cancer prevention and treatment from the perspective of healthcare policy-makers (i.e. supply side) and to investigate whether there is a difference between the estimated WTP in two scenarios.

METHODS

We conducted a web-based survey from May to July 2022 among experts who offering consultation to the government. We surveyed 79 experts from a national think-tank (84.81% response rate) using contingent valuation method, a method for estimating the monetary value that individuals place on a non-market service.

RESULTS

The mean WTP for two scenarios were estimated at 1.29 times of per capita Gross Domestic Product (GDP) of China and 1.90 times of per capita GDP, respectively. There was a difference between the WTP in the two scenarios and the WTP for treatment was significantly higher than prevention.

CONCLUSION

The findings suggest that though there is a smaller gap between the two scenarios in China as compared to other countries, the WTP may vary under different scenarios. So there's a need to further refine the development of CET by adding parameters like prevention instead of defining one universal threshold.

Estimating the cost-effectiveness threshold of advanced non-small cell lung cancer in China using mean opportunity cost and contingent valuation method

OBJECTIVES

Monetizing health has sparked controversy and has implications for pricing strategies of emerging health technologies. Medical insurance payers typically set up thresholds for quality-adjusted life years (QALY) gains based on health productivity and budget affordability, but they rarely consider patient willingness-to-pay (WTP). Our study aims to compare Chinese payer threshold and patient WTP toward QALY gain of advanced non-small cell lung cancer (NSCLC) and to inform a potential inclusion of patient WTP under more complex decision-making scenarios.

METHODS

A regression model was constructed with cost as the independent variable and QALY as the dependent variable, where the regression coefficients reflect mean opportunity cost, and by transforming these coefficients, the payer threshold can be obtained. Patient WTP was elicited through a contingent valuation method survey. The robustness of the findings was examined through sensitivity analyses of model parameters and patient heterogeneity.

RESULTS

The payer mean threshold in the base-case was estimated at 150,962 yuan (1.86 times per capita GDP, 95% CI 144,041-159,204). The two scenarios analysis generated by different utility inputs yielded thresholds of 112,324 yuan (1.39 times per capita GDP) and 111,824 yuan (1.38 times per capita GDP), respectively. The survey included 85 patients, with a mean WTP of 148,443 yuan (1.83 times per capita GDP, 95% CI 120,994-175,893) and median value was 106,667 yuan (1.32 times the GDP per capita). Due to the substantial degree of dispersion, the median was more representative. The payer threshold was found to have a high probability (98.5%) of falling within the range of 1-2 times per capita GDP, while the robustness of patient WTP was relatively weak.

CONCLUSIONS

In China, a country with a copayment system, payer threshold was higher than patient WTP, indicating that medical insurance holds significant decision-making authority, thus temporarily negating the need to consider patient WTP.

A Decade of Health Innovation: The Impact of New Medicines on Patient Health and the Implications for NICE's Size of Benefit Multiplier

OBJECTIVES

This study aimed to estimate the incremental health benefits of pharmaceutical innovations approved between 2011 and 2021 and the share that would surpass the National Institute for Health and Care Excellence (NICE) "size of benefit" decision weight thresholds.

METHODS

We identified all US-approved drugs between 2011 and 2021. Health benefits, in terms of quality-adjusted life-years (QALYs) for each treatment, were extracted from published cost-effectiveness analyses. Summary statistics by therapeutic area and cell/gene therapy status identified the treatments with the largest QALY gains.

RESULTS

The Food and Drug Administration approved 483 new therapies between 2011 and 2021 and of these 252 had a published cost-effectiveness analysis meeting our inclusion criteria. The average incremental health benefits produced by these treatments were 1.04 QALYs (SD = 2.00) relative to standard of care, with wide variation by therapeutic area. Pulmonary and ophthalmologic therapies produced the highest health benefits with 1.47 (SD = 2.17, n = 13) and 1.41 QALYs gained (SD = 3.53, n = 7), respectively; anesthesiology and urology had the lowest gains (< 0.1 QALYs). Cell and gene therapies produced an average health benefit that was 4 times greater than noncell and gene therapies (4.13 vs 0.96). Among the top treatments in terms of incremental QALYs gained, half (10 of 20) were oncology therapies. Three of 252 treatments (1.2%) met NICE's threshold for a "size of benefit" multiplier.

CONCLUSIONS

Treatments for rare disease, oncology, and cell and gene therapies produced some of the highest level of health innovation relative to previous standard of care, but few therapies would have qualified for NICE's "size of benefit" multiplier as currently constructed.

Willingness to Pay for One Additional Quality Adjusted Life Year: A Population Based Survey from China

OBJECTIVE

The aim of this study was to estimate the population's willingness to pay (WTP) for an additional quality-adjusted life-year (QALY) in China.

METHODS

The WTP for an additional QALY (WTP/Q) was estimated using a contingent valuation survey with quota sampling and snowball sampling, using a pre-designed questionnaire with 18 hypothetical scenarios. The change in health state was depicted by the EQ-5D-5L. The questionnaires were completed by telephone and face-to-face interviews. Two-part regression models were used to test validity and how different factors affect WTP/Q.

RESULTS

A total of 2008 people participated in this survey and provided 3265 WTP responses for further analysis. The average WTP/Q for the entire sample is 113,120 Renminbi (RMB) (USD 16,884), which is 1.75 times the gross domestic product (GDP) per capita. For the quality-of-life improvement scenarios, the mean WTP/Q is RMB 78,907 (USD 11,777, 1.22 times GDP per capita), which is significantly lower than the life extension scenarios (RMB 177,761, USD 26,531, 2.76 times GDP per capita). Age was found to be negatively related to positive WTP. Educational level was positively related to the probability of reporting positive WTP and the level of WTP/Q. Although the EQ-5D-5L utility scores of respondents did not prove to be statistically significant determinants of WTP/Q, the two dimensions of EQ-5D-5L, pain/discomfort and anxiety/depression, had an impact on WTP/Q. In addition, WTP/Q was higher when the health outcome had a 50% probability of occurring than when the health outcome was 100% certain. WTP/Q was higher when a lower health gain was presented to the respondent.

CONCLUSION

This study provides empirical evidence of the monetary value of an additional QALY from a sample of the Chinese population. In addition, a higher threshold for end-of-life therapies should be considered.

Estimating the range of incremental cost-effectiveness thresholds for healthcare based on willingness to pay and GDP per capita: A systematic review

Background

Decision-making in healthcare policy involves assessing both costs and benefits. In determining the cost-effectiveness (CE) threshold, willingness to pay (WTP) per quality-adjusted life year (QALY), GDP per capita, and other factors are important. However, the relationship between WTP/QALY or GDP per capita and the CE threshold is unclear. It is important to clarify the relationship between WTP/QALY and GDP to provide a clear basis for setting the CE threshold.

Objective

The purpose of this study was to compare WTP/QALY and GDP per capita, and to develop a new CE threshold range based on WTP using GDP per capita. The relationship between WTP/QALY and healthy life expectancy (HALE) was also investigated.

Methods

We searched MEDLINE, EMBASE and Web of Science from 1980/01/01 to 2020/12/31 using the following selection criteria (latest search: Dec 2021):1, studies that estimated WTP/QALY; 2, the general population was surveyed; 3, the article was in English. From the collected articles, we obtained average values of WTP/QALY for various countries and compared WTP/QALY with GDP per capita. The correlation between WTP/QALY and HALE was also examined.

Results

We identified 20 papers from 17 countries. Comparison of mean WTP/QALY values with GDP per capita showed that most WTP/QALY values were in the range of 0.5–1.5 times GDP per capita, though the median values were less than 0.5 times. Comparison of WTP/QALY with HALE showed a statistically significant positive correlation when Taiwan was excluded as an outlier.

Conclusions

Our results suggest a CE threshold range of 0.5–1.5 times GDP per capita is appropriate but lower than the WHO-recommended range of 1–3 times. The correlation between WTP/QALY and HALE suggests that investment in healthcare is reflected in an increased healthy life expectancy. Since WTP is based on consumer preferences, this range could be used to set a generally acceptable criterion.

Willingness to pay for a quality-adjusted life year: a systematic review with meta-regression

The use of a threshold for cost-utility studies is of major importance to health authorities for making the best allocation decisions for limited resources. Regarding the increasing number of studies worldwide that seek to establish a value for a quality-adjusted life year (QALY), it is necessary to review these studies to provide a global insight into the literature. A systematic review on willingness to pay (WTP) studies focusing on QALY was conducted in eight databases up to June 26, 2020. From a total of 9991 entries, 39 studies were selected, and 511 observations were extracted for the meta-analysis using the ordinary least squares method. The results showed a predicted mean empirical value of $52,619.39 (95% CI 49,952.59; 55,286.19) per QALY in US dollars for 2018. A 1% increase in income led to an increase of 0.6% in the WTP value, while a 1-year increase in respondent age led to a decrease of 3.3% in the WTP value. Sex, education level and employment status had significant effects on WTP. Compared to face-to-face interviews, surveys conducted by the internet or telephone were more likely to have a significantly higher value of WTP per QALY, while out-of-pocket payment tended to lower the value. The prediction made for the province of Quebec, Canada, provided a QALY value of approximately USD $98,450 (CAD $127,985), which is about 2.3 times its gross domestic product (GDP) per capita in 2018. This study is consistent with the extant literature and will be useful for countries that do not yet have a preference-based survey for the value of a QALY.

Monetary Valuation of a Quality-Adjusted Life Year (QALY) for Depressive Disorders Among Patients and Non-Patient Respondents: A Matched Willingness to Pay Study

Background

As estimated by the World Health Organization, depressive disorders will be the leading contributor to the Global Burden of Disease by 2030. In light of this fact, we designed a study whose aim was to investigate whether the value placed on health-related quality of life (HRQoL) for a depressive disorder is higher in patients diagnosed with a major depressive disorder (MDD) compared to non-patients in a matched sample.

Method

We collected data on willingness to pay (WTP) for a total of four health-gain scenarios, which were presented to 18 outpatients diagnosed with a MDD versus 18 matched non-patient respondents with no symptoms of depression. Matching characteristics included age, income, level of education, and type of health insurance. Respondents were presented with different HRQoL scenarios in which they could choose to pay money to regain their initial health state through various treatment options (e.g., inpatient treatment, electroconvulsive therapy). To test whether the probability of stating a positive WTP differed significantly between the two samples, Fisher's exact test was used. Differences regarding stated WTP between the samples were investigated using the Mann-Whitney U-test.

Results

For most of the health scenarios, the probability of stating a positive WTP did not differ between the two samples. However, patient respondents declared WTP values up to 7.4 times higher than those stated by matched non-patient respondents.

Conclusion

Although the perceived necessity to pay for mental-HRQoL gains did not differ between respondents with MDD and respondents with no symptoms of depression, patient respondents stated higher values.

A Systematic Review of Demand-Side Methods of Estimating the Societal Monetary Value of Health Gain

OBJECTIVES

Although many reviews of the literature on cost-effectiveness thresholds (CETs) exist, the availability of new studies and the absence of a fully comprehensive analysis warrant a new review. This study systematically reviews demand-side methods for estimating the societal monetary value of health gain.

METHODS

Several electronic databases were searched from inception to October 2019. To be included, a study had to be an original article in any language, with a clearly described method for estimating the societal monetary values of health gain and with all estimated values reported. Estimates were converted to US dollars ($), using purchasing power parity (PPP) exchange rates and the gross domestic product (GDP) per capita (2019).

RESULTS

We included 53 studies; 45 used direct approach and 8 used indirect approach. Median estimates from the direct approach were PPP$ 24 942 (range 554-1 301 912) per quality-adjusted life-year (QALY), which were typically 0.53 (range 0.02-24.08) GDP per capita. Median estimates using the indirect approach were PPP$ 310 051 (range 36 402-7 574 870) per QALY, which accounted for 7.87 (range 0.68-116.95) GDP per capita.

CONCLUSIONS

Our review found that the societal values of health gain or CETs were less than GDP per capita. The great variety in methods and estimates suggests that a more standardized and internationally agreed methodology for estimating CET is warranted. Multiple CETs may have a role when QALYs are not equally valued from a societal perspective (eg, QALYs accruing to people near death compared with equivalent QALYs to others).

Comparing the monetary value of a quality-adjusted life year from the payment card and the open-ended format

BACKGROUND

The payment card (PC) format and the open-ended (OE) format are common methods in eliciting willingness-to-pay (WTP) of one additional quality-adjusted life year (QALY). The aim of this research is to compare these two formats in eliciting the monetary value of a QALY.

METHODS

A contingent valuation survey was carried out using a pre-designed questionnaire with various hypothetical scenarios. The difference between the PC and the OE formats was evaluated by a two-sample equality test. Furthermore, generalized linear models were carried out to control observed heterogeneity and to test theoretical validity.

RESULTS

In total, 461 individuals were involved, among whom 235 (51%) answered the PC question, while 226 (49%) answered the OE question. Excluding zero response, the mean WTP values of these two formats for different scenarios varied dramatically, which was from 13,278 to 280,177 RMB for the PC, 18,119 to 620,913 RMB for the OE. The OE format tended to elicit lower values for less serious condition and higher values for more serious condition. However, equality test of mean and median demonstrated insignificant difference of these two formats for all scenarios. For both OE and PC format, most variables were found to have significant effect on the value of WTP/QALY. Moreover, joint estimation indicated a statistically significant positive effect on the OE results. Further analysis demonstrated that the imbalanced zero response distribution caused the main difference of these two formats.

CONCLUSIONS

This research indicated insignificantly different WTP/QALY estimates of the PC format and OE format with the grouped data whereas significantly higher estimates of the OE format from the pooled data. These two formats were found to be valid. More research about the difference and the validity of various WTP eliciting methods would be recommended for a robust estimation of WTP/QALY.

Examining Willingness-to-Pay and Zero Valuations for a Health Improvement with Logistic Regression

Study aim was to elicit the Greek general population’s willingness-to-pay (WTP) for a health improvement (recovery to perfect health), examine attitudinal differences between willing- and unwilling-to-pay individuals regarding healthcare services provision, and investigate —using a logistic regression model—demographic/socioeconomic factors impact on their intention to pay for a health improvement. A research tool was developed to conduct a cross-sectional stated-preference telephone-based survey (January-February 2019) and a representative sample (n = 1342) of the Greek general population was queried. The computer-assisted telephone-interview (CATI) method was used to ensure random sampling. WTP was elicited using the iterative bidding technique. Participants’ attitudes toward healthcare services provision were assessed through pre-defined statements. Test-retest reliability of these statements was assessed using intraclass correlation coefficients (ICC). Logistic regression was employed to identify sociodemographic factors’ effect on WTP intention. Differences among individuals’ attitudes were assessed using the chi-square test. All analyses were conducted using the IBM SPSS Software v.25.0. Analysis showed acceptable reliability for WTP estimates (ICC = .67) and good reliability for healthcare services assessment statements (ICC = .83-.94). Mean WTP was estimated at €439.8. Respondents with higher educational level and higher household income were more likely to be willing to pay for a health improvement. On the contrary, older participants were less likely to be willing to pay. Most participants who considered public healthcare services to be of high quality were unwilling to pay. Logistic regression analysis led to the development of an effective predictive model regarding factors affecting individuals’ WTP intention for a health improvement. Further classification of unwilling-to-pay individuals into protest responders and “true” zero valuators showed that protest responders are unlikely to be representative of the population. Hence, study results can be used for debiasing WTP responses, leading to a more accurate use of WTP estimates by policy makers, exploiting WTP values in medical interventions cost-benefit analysis within reimbursement decisions framework.

Willingness to pay for a quality-adjusted life year for depressive disorders compared to heart disease based on population preferences

PURPOSE

According to estimations of the World Health Organization, depressive disorders, and cardiovascular disease will be the leading causes for global burden of disease in 2030. The aim of the present study was to estimate the value a representative sample of the German population places on quality-adjusted life years (QALYs) for depressive disorders compared to heart disease.

METHODS

A representative sample of N = 967 of the German general public was randomly presented with one of two hypothetical health-loss scenarios: One version of the questionnaire presented respondents with health loss due to depression, while the other version dealt with health loss due to experiencing a heart disease. Respondents were asked to indicate their willingness to pay (WTP) for four hypothetical health-gain scenarios with different treatment options.

RESULTS

In the depression questionnaire median WTP values ranged from 1000 to 1500 EUR; in the heart disease questionnaire from 1000 to 2000 EUR. Results of the Mann-Whitney U-Test and Median Test indicate higher WTP values for heart disease compared to depressive disorders when QALY gains were minor and stretched over a long period of time, and when treatment with bypass operation (rather than treatment with ECT) was offered. Zero WTP was significantly higher in all scenarios of the depression questionnaire in comparison to the hearth disease questionnaire.

CONCLUSION

Results indicate that respondents valued the necessity of paying for treatment higher when presented with heart disease compared to depression.

Sample restrictions and the elicitation of a constant willingness to pay per quality adjusted life year

It is well established that the underlying theoretical assumptions needed to obtain a constant proportional trade-off between a quality adjusted life year (QALY) and willingness to pay (WTP) are restrictive and often empirically violated. In this paper, we set out to investigate whether the proportionality conditions (in terms of scope insensitivity and severity independence) can be satisfied when data is restricted to include only respondents who pass certain consistency criteria. We hypothesize that the more we restrict the data, the better the compliance with the requirement of constant proportional trade-off between WTP and QALY. We revisit the Danish data from the European Value of a QALY survey eliciting individual WTP for a QALY (WTP-Q). Using a "chained approach" respondents were first asked to value a specified health state using the standard gamble (SG) or the time-trade-off (TTO) approach and subsequently asked their WTP for QALY gains of 0.05 and 0.1 (tailored according to the respondent's SG/TTO valuation). Analyzing the impact of the different exclusion criteria on the two proportionality conditions, we find strong evidence against a constant WTP-Q. Restricting our data to include only respondents who pass the most stringent consistency criteria does not impact on the performance of the proportionality conditions for WTP-Q.

Value of Electroconvulsive Therapy in the General Public: A Willingness to Pay Study in Germany

OBJECTIVE

The aims of this study were to estimate the value a population-representative sample places on electroconvulsive therapy (ECT) through willingness to pay (WTP) and to assess the effects of individual characteristics on WTP for ECT.

METHODS

A German population-representative sample of 518 was presented with a hypothetical health loss scenario of depression and was asked to indicate WTP for ECT. Probit and quantile regression were used to estimate the effects of individual characteristics on the probability of stating a positive WTP and on the amount of money respondents were willing to pay.

RESULTS

Two thirds of respondents stated that they had no knowledge about ECT. Most (56.5%) respondents indicated zero WTP for health gains through ECT treatment. Mean WTP was €5201 ($5612); median WTP was €1000 ($1079). Respondents' monthly household income had a significant effect on the probability of stating a positive WTP. Assessing WTP above zero, income showed a significant positive effect, whereas a higher score of depressive complaints showed a significant negative effect on the amount respondents were willing to pay.

CONCLUSION

Knowledge about ECT treatment is particularly low in the German public.

A systematic review and meta-regression of studies eliciting willingness-to-pay per quality-adjusted life year in the general population

OBJECTIVES

From the demand-side perspective, the monetary value of one additional quality-adjusted life year (QALY) is estimated as willingness-to-pay per QALY (WTPQ). This study aims to summarize the methods and contexts of elicitation of willingness-to-pay per quality-adjusted life year (WTPQ) in the general population and to investigate the heterogeneity of WTPQ estimates.

METHODS

Meta-regression analysis was conducted using Comprehensive Meta-Analysis Software. Sensitivity analyses were undertaken by replacing the lowest and highest 5% and 2.5% of WTPQ by percentiles.

RESULTS

33 studies with 102 WTPQ estimates were included. The overall mean and median WTPQ estimates are $1,280,002 and $44,072, respectively. The meta-regressions demonstrated that types of health gain (quality of life or life length) and certainty of health outcomes are statistically significant factors. Furthermore, compared with online interviews, face-to-face interviews tend to yield lower WTPQ. Moreover, the declining trend of QALY gains and positive effect with statistical significance of the sample age were also noticed.

CONCLUSION

For valid and representative values of WTPQ, future researchers should therefore take into consideration various scenarios and investigate both health gain with certainty and uncertainty, health gain from both life length and quality of life, and different size of QALY gains.

A Contingent Valuation Study for Eliciting a Monetary Value of a Quality-Adjusted Life-Year in the General Greek Population

OBJECTIVES

To elicit a willingness-to-pay (WTP) per quality-adjusted life-year (QALY) estimate for the general Greek population and assess the impact of individuals' socio-demographic characteristics and motives on this estimate.

METHODS

A telephone-based survey was carried out employing a representative sample of the general Greek population (n = 1342). A computer-assisted telephone-interview method was adopted to ensure random sampling. A total of 528 participants reported a WTP value for a utility improvement from their current health to perfect health. Those individuals' motives were assessed through predefined statements. Test-retest reliability was assessed using intraclass correlation coefficient (ICC). Multiple linear regression (MLR) and one-way analysis of variance (ANOVA) tests were conducted to assess the effect of socioeconomic/demographic determinants and motive statements, respectively, on WTP/QALY. MLR was re-estimated considering as dependent variable the WTP/QALY estimate calculated for participants: (1) stating a WTP value ≤ their household income and (2) presenting higher certainty regarding stated WTP value (sensitivity analysis).

RESULTS

Analysis revealed good reliability for WTP/QALY estimates and motive statements (ICC values > 0.8). Mean WTP/QALY was €26 280. The respective 5% trimmed value was €14 862. Being a student and household income affected WTP/QALY. Sensitivity analysis did not produce markedly different WTP/QALY predictors, implying the robustness of results, irrespective of the participant group considered. Individuals who indicated the inability to cover basic family needs or pay tax claims as motives reported lower WTP/QALY values compared with those not viewing these aspects as motives.

CONCLUSIONS

Findings confirm that the World Health Organization's criterion used currently in Greek cost-effectiveness studies is not unreasonable. Additional research is essential to further explore WTP/QALY estimates in the Greek setting and facilitate informed decision making.

Economic value of protected areas via visitor mental health

We evaluate methods to calculate the economic value of protected areas derived from the improved mental health of visitors. A conservative global estimate using quality-adjusted life years, a standard measure in health economics, is US$6 trillion p.a. This is an order of magnitude greater than the global value of protected area tourism, and two to three orders greater than global aggregate protected area management agency budgets. Future research should: refine this estimate using more precise methods; consider interactions between health and conservation policies and budgets at national scales; and examine links between personalities and protected area experiences at individual scale.

Factors and Minimal Subsidy Associated with Tea Farmers’ Willingness to Adopt Ecological Pest Management

Scientific assessment related to the externalities of the tea ecological pest management (TEPM) system that can affect socio-economic development and ecological benefits is important to the sustainable development of the tea industry. This paper used the contingent valuation method to evaluate the externalities associated with TEPM and the factors affecting its adoption by farmers through survey data collected from Anxi county, Fujian province, China. The results showed that the positive externalities, which were not internalized (embodied in price), affected the willingness of tea farmers to adopt TEPM. The willingness to accept a subsidy for adopting the TEPM system was significantly affected by the individual tea farmer’s age, education level, income, plantation, knowledge of human health and risk preference. The compensation threshold of externalities for TEPM was 5668.80 yuan per hectare per year. It is suggested that the government should adopt this threshold as a minimum subsidy to mitigate information asymmetry in two markets, namely ecological management technology and trading between suppliers and buyers of tea products. Finally, production stability and improved price for high quality tea resulting from healthy ecology in TEPM could enhance positive externalities. This coupled with other benefits, such as a reduction in the amount of resources spent on pesticides, could result in governmental subsidies for TEPM being gradually reduced over time.

Value of a QALY and VSI estimated with the chained approach

The value of a quality-adjusted life-year (QALY) and the value of a statistical injury (VSI) are important measures within health economics and transport economics. Several studies have, therefore, estimated people's willingness to pay (WTP) for these estimates, but most results show scale insensitivity. The 'original' chained approach (CA) is a method developed to mitigate this problem by combining the contingent valuation (CV) with standard gamble (SG). In contrast to the version of the CA applied by the previous research of the WTP for a QALY, the original version allows the value of major health gains to be estimated without having the respondents express their WTP directly. The objective of this study was to estimate the value of a QALY and VSI in the context of non-fatal road traffic accidents using the original CA to test if the approach, applied to a wide range of health gains, is able to derive valid estimates and a constant value of a QALY which the previous research has not been able to show. Data were collected from a total of 800 individuals in the Swedish adult general population using two web-based questionnaires. The values of a QALY based on trimmed estimates were close to constant at €300,000 irrespective of the size of the QALY gain. The study shows that the original CA method may be a valid method to estimate the value of a QALY and VSI for major health losses. It also supports the use of a higher threshold value for a QALY than that which is currently applied by several health technology assessment agencies in different countries.