US Valuation Research Articles

Cost per quality-adjusted life year gained of revision neural decompression and instrumented fusion for same-level recurrent lumbar stenosis: defining the value of surgical intervention

Despite advances in technology and understanding in spinal physiology, reoperation for symptomatic same-level recurrent stenosis continues to occur. Although revision lumbar surgery is effective, attention has turned to the question of the utility and value of revision decompression and fusion procedures. To date, an analysis of cost and heath state gain associated with revision lumbar surgery for recurrent same-level lumbar stenosis has yet to be described. The authors set out to assess the 2-year comprehensive cost of revision surgery and determine its value in the treatment of same-level recurrent stenosis. Forty-two patients undergoing revision decompression and instrumented fusion for same-level recurrent stenosis-associated leg and back pain were included in this study. Two-year total back-related medical resource utilization, missed work, and health state values (quality-adjusted life years [QALYs], calculated from the EQ-5D with US valuation) were assessed. Two-year resource use was multiplied by unit costs based on Medicare national allowable payment amounts (direct cost), and patient and caregiver workday losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). Mean total 2-year cost per QALY gained after revision surgery was assessed. The mean (± SD) interval between prior and revision surgery was 4.16 ± 4.64 years. Bone morphogenetic protein was used in 7 cases of revision arthrodesis (16.7%). A mean cumulative 2-year gain of 0.84 QALY was observed after revision surgery. The mean total 2-year cost of revision fusion was $49,431 ± $7583 (surgery cost $21,060 ± $4459; outpatient resource utilization cost $9748 ± $5292; indirect cost $18,623 ± $9098). Revision decompression and extension of fusion was associated with a mean 2-year cost per QALY gained of $58,846. In the authors' practice, revision decompression and fusion provided a significant gain in health state utility for patients with symptomatic same-level recurrent stenosis, with a 2-year cost per QALY gained of $58,846. When indicated, revision surgery for same-level recurrent stenosis is a valuable treatment option for patients experiencing back and leg pain secondary to this disease. The authors' findings provide a value measure of surgery that can be compared with the results of future cost-per-QALY-gained studies of medical management or alternative surgical approaches.

Cost per quality-adjusted life year gained of laminectomy and extension of instrumented fusion for adjacent-segment disease: defining the value of surgical intervention

Over the past decade, there has been a dramatic increase in the number of spinal fusions performed in the US and a corresponding increase in the incidence of adjacent-segment disease (ASD). Surgical management of symptomatic ASD consists of decompression of neural elements and extension of fusion. It has been shown to have favorable long-term outcomes, but the cost-effectiveness remains unclear. In this study, the authors set out to assess the cost-effectiveness of revision surgery in the treatment of ASD over a 2-year period. Fifty patients undergoing neural decompression and extension of fusion construct for ASD-associated back and leg pain were included in the study. Two-year total back-related medical resource utilization, missed work, and health state values (quality-adjusted life years [QALYs], calculated from the EQ-5D with US valuation) were assessed. Two-year resource use was multiplied by unit costs based on Medicare national allowable payment amounts (direct cost), and patient and caregiver workday losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). Mean total 2-year cost per QALY gained after revision surgery was assessed. The mean (± SD) interval between prior fusion and revision surgery for ASD was 3.07 ± 2.02 years. A mean cumulative 2-year gain of 0.76 QALYs was observed after revision surgery. The mean total 2-year cost of extension of fusion constructs was $47,846 ± $32,712 (surgery cost: $24,063 ± $300; outpatient resource utilization cost: $4175 ± $3368; indirect cost: $19,607 ± $32,187). Revision decompression and extension of fusion was associated with a mean 2-year cost per QALY gained of $62,955. In the authors' practice, revision decompression and extension of fusion provided a significant gain in health state utility for patients with symptomatic ASD, with a 2-year cost per QALY gained of $62,995. When indicated, revision surgery for ASD is a valuable treatment option for patients experiencing back and leg pain secondary to ASD. The findings provide a value measure of surgery that can be compared with future cost-per-QALY-gained studies of medical management or alternative surgical approaches.

Revisiting United States valuation of EQ-5D states

In the original US valuation study of EQ-5D states, all worse-than-dead time trade-off responses (26% of the sample) were divided by 39 to increase the QALY estimates. This transformation has no theoretical justification and motivates this re-examination. Using the publically available dataset, we compared three alternative random utility models: instant (IRUM), angular (ARUM), and episodic (ERUM) models. Each leads to a distinct econometric estimator: mean ratio, ratio of means, and coefficient, respectively. IRUM suggests that 203 of the 243 EQ-5D states are worse-than-dead, which has little face validity compared to ARUM and ERUM (42 and 3 WTD states). ARUM and ERUM estimates are proportionally related such that losses in QALYs are approximately 37% larger under ARUM than ERUM. Compared to ERUM, economic evaluations using ARUM estimates emphasize quality of life, and this difference may influence policy decisions. Either ERUM or ARUM values sets are recommended over the original, transformed set.

Cost-effectiveness of multilevel hemilaminectomy for lumbar stenosis–associated radiculopathy

Laminectomy for lumbar stenosis-associated radiculopathy is associated with improvement in pain, disability, and quality of life. However, given rising health-care costs, attention has been turned to question the cost-effectiveness of lumbar decompressive procedures. The cost-effectiveness of multilevel hemilaminectomy for radiculopathy remains unclear. To assess the comprehensive medical and societal costs of multilevel hemilaminectomy at our institution and determine its cost-effectiveness in the treatment of degenerative lumbar stenosis. Prospective single cohort study. Fifty-four consecutive patients undergoing multilevel hemilaminectomy for lumbar stenosis-associated radiculopathy after at least 6 months of failed conservative therapy were included. Self-reported measures were assessed using an outcomes questionnaire that incorporated total back-related medical resource utilization, missed work, and improvement in leg pain (visual analog scale for leg pain [VAS-LP]), disability (Oswestry Disability Index [ODI]), quality of life (Short Form-12 [SF-12]), and health state values (quality-adjusted life years [QALYs], calculated from EuroQuol 5D [EQ-5D] with US valuation). Over a 2-year period, total back-related medical resource utilization, missed work, and improvement in leg pain (VAS-LP), disability (ODI), quality of life (SF-12), and health state values (QALYs, calculated from EQ-5D with US valuation) were assessed. Two-year resource use was multiplied by unit costs based on Medicare national allowable payment amounts (direct cost), and patient and caregiver workday losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). Mean total 2-year cost per QALY gained after multilevel hemilaminectomy was assessed. Compared with preoperative health states reported after at least 6 months of medical management, a significant improvement in VAS-LP, ODI, and SF-12 (physical and mental components) was observed 2 years after multilevel hemilaminectomy, with a mean 2-year gain of 0.72 QALYs. Mean±standard deviation total 2-year cost of multilevel hemilaminectomy was $24,264±10,319 (surgery cost, $10,220±80.57; outpatient resource utilization cost, $3,592±3,243; and indirect cost, $10,452±9,364). Multilevel hemilaminectomy was associated with a mean 2-year cost per QALY gained of $33,700. Multilevel hemilaminectomy improved pain, disability, and quality of life in patients with lumbar stenosis-associated radiculopathy. Total cost per QALY gained for multilevel hemilaminectomy was $33,700 when evaluated 2 years after surgery with Medicare fees, suggesting that multilevel hemilaminectomy is a cost-effective treatment of lumbar radiculopathy.

Erratum: Cost-effectiveness of transforaminal lumbar interbody fusion for Grade I degenerative spondylolisthesis

Object Transforaminal lumbar interbody fusion (TLIF) for spondylolisthesis-associated back and leg pain is associated with improvement in pain, disability, and quality of life. However, given the rising health care costs associated with spinal fusion procedures and varying results of recent cost-utility studies, the cost-effectiveness of TLIF remains unclear. The authors set out to assess the comprehensive costs of TLIF at their institution and to determine its cost-effectiveness in the treatment of degenerative spondylolisthesis. Methods Forty-five patients undergoing TLIF for Grade I degenerative spondylolisthesis–associated back and leg pain after 6–12 months of conservative therapy were included. The authors assessed the 2-year back pain visual analog scale (VAS) score, leg pain VAS score, Oswestry Disability Index, and total back-related medical resource utilization, missed work, and health-state values (quality-adjusted life years [QALYs], calculated from EQ-5D with US valuation). Two-year resource ...

Cost-effectiveness of transforaminal lumbar interbody fusion for Grade I degenerative spondylolisthesis

Transforaminal lumbar interbody fusion (TLIF) for spondylolisthesis-associated back and leg pain is associated with improvement in pain, disability, and quality of life. However, given the rising health care costs associated with spinal fusion procedures and varying results of recent cost-utility studies, the cost-effectiveness of TLIF remains unclear. The authors set out to assess the comprehensive costs of TLIF at their institution and to determine its cost-effectiveness in the treatment of degenerative spondylolisthesis. Forty-five patients undergoing TLIF for Grade I degenerative spondylolisthesis-associated back and leg pain after 6-12 months of conservative therapy were included. The authors assessed the 2-year back pain visual analog scale (VAS) score, leg pain VAS score, Oswestry Disability Index, and total back-related medical resource utilization, missed work, and health-state values (quality-adjusted life years [QALYs], calculated from EQ-5D with US valuation). Two-year resource use was multiplied by unit costs based on Medicare national allowable payment amounts (direct cost), and patient and caregiver workday losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). The mean total 2-year cost per QALY gained after TLIF was assessed. Compared with preoperative health states reported after at least 6 months of medical management, a significant improvement in back pain VAS score, leg pain VAS score, and Oswestry Disability Index was observed 2 years after TLIF, with a mean 2-year gain of 0.86 QALYs. The mean ± SD total 2-year cost of TLIF was $36,836 ± $11,800 (surgery cost, $21,311 ± $2800; outpatient resource utilization cost, $3940 ± $2720; indirect cost, $11,584 ± $11,363). Transforaminal lumbar interbody fusion was associated with a mean 2-year cost per QALY gained of $42,854. Transforaminal lumbar interbody fusion improved pain, disability, and quality of life in patients with degenerative spondylolisthesis-associated back and leg pain. The total cost per QALY gained for TLIF was $42,854 when evaluated 2 years after surgery with Medicare fees, suggesting that TLIF is a cost-effective treatment of lumbar spondylolisthesis.

Gender differences in health-related quality-of-life are partly explained by sociodemographic and socioeconomic variation between adult men and women in the US: evidence from four US nationally representative data sets.

PurposeThe purpose of this study was to describe gender differences in self-reported health-related quality-of-life (HRQoL) and to examine whether differences are explained by sociodemographic and socioeconomic status (SES) differentials between men and women.MethodsData were from four US nationally representative surveys: US Valuation of the EuroQol EQ-5D Health States Survey (USVEQ), Medical Expenditure Panel Survey (MEPS), National Health Measurement Study (NHMS) and Joint Canada/US Survey of Health (JCUSH). Gender differences were estimated with and without adjustment for sociodemographic and SES indicators using regression within and across data sets with SF-6D, EQ-5D, HUI2, HUI3 and QWB-SA scores as outcomes.ResultsWomen have lower HRQoL scores than men on all indexes prior to adjustment. Adjusting for age, race, marital status, education and income reduced but did not remove the gender differences, except with HUI3. Adjusting for marital status or income had the largest impact on estimated gender differences.ConclusionsThere are clear gender differences in HRQoL in the United States. These differences are partly explained by sociodemographic and SES differentials.

A comparison of United States and United Kingdom EQ‐5D health states valuations using a nonparametric Bayesian method

Cost-effectiveness analysis of alternative medical treatments relies on having a measure of effectiveness, and many regard the quality adjusted life year (QALY) to be the current 'gold standard.' In order to compute QALYs, we require a suitable system for describing a person's health state, and a utility measure to value the quality of life associated with each possible state. There are a number of different health state descriptive systems, and we focus here on one known as the EQ-5D. Data for estimating utilities for different health states have a number of features that mean care is necessary in statistical modelling.There is interest in the extent to which valuations of health may differ between different countries and cultures, but few studies have compared preference values of health states obtained from different countries. This article applies a nonparametric model to estimate and compare EQ-5D health state valuation data obtained from two countries using Bayesian methods. The data set is the US and UK EQ-5D valuation studies where a sample of 42 states defined by the EQ-5D was valued by representative samples of the general population from each country using the time trade-off technique. We estimate a utility function across both countries which explicitly accounts for the differences between them, and is estimated using the data from both countries. The article discusses the implications of these results for future applications of the EQ-5D and for further work in this field.

A Median Model for Predicting United States Population-Based EQ-5D Health State Preferences

The D1 model that was developed to predict US societal preferences for EQ-5D health states addressed several important conceptual and statistical issues. However, it has been criticized for being too complex, failing to account for the nonnormal distribution of health state values, and the transformation of preferences for worse-than-death health states before estimation. This research was conducted to develop an improved model for predicting median preferences for EQ-5D health states for the US population. Probability-weighted least absolute deviations regression was used to fit models to the time trade-off data collected in the US Valuation of the EQ-5D Health States study. No transformation was applied to the values for states considered worse than death. Several model specifications that differed with respect to explanatory variables were evaluated using two-sample cross-validation. The best-fitting model included only fixed effects for moderate or severe problems in each of the 5 EQ-5D dimensions and excluded a constant. This specification yielded rank correlations between observed and predicted values and median observed and predicted values of 0.635 and 0.991, respectively, as well as a median absolute error of 0.026. The predicted median preferences ranged from 1.00 for full health, to -0.81 for the worst possible health state. Due to its simplicity and robustness, a median model is superior to other models for predicting US population preferences for EQ-5D health states. The predictions of this model are suggested for use in applications that require US societal health state values.

The association of survey language (Spanish vs. English) with Health Utilities Index and EQ-5D index scores in a United States population sample

To explore whether variations in the EQ-5D, Health Utilities Index (HUI) Mark II (HUI2), and HUI Mark III (HUI3) index scores were associated with the survey language (Spanish vs. English) in the US Valuation of the EQ-5D Health States study. The EQ-5D, HUI2, and HUI3 index scores were compared across three language/ethnic groups (i.e., non-Hispanics surveyed in English [NHE], Hispanics surveyed in English [HE], and Hispanics surveyed in Spanish [HS]) using multiple regression models. Of the 4,033 respondents, 568 elected to be surveyed in Spanish. After controlling for socioeconomic and health-related variables, the mean difference (standard error) in EQ-5D, HUI2, and HUI3 index scores between HS and NHE were 0.014 (0.011), 0.050 (0.012), and 0.071 (0.020), respectively. After controlling for potential confounding variables, HS were less likely than NHE to report problems/disabilities in HUI2/3 health attributes of vision, speech, self-care, emotion, pain, and cognition (range of odds ratios: 0.31-0.45, P < 0.01 for all). No important differences were found in EQ-5D dimensions between any groups or in any of the index scores between HE and NHE. Health researchers studying health status of culturally diverse populations should be aware that different preference-based health indices may lead to different results.

Mode of Administration Is Important in US National Estimates of Health-Related Quality of Life

It is unknown if different national surveys that vary in mode of administration yield similar national averages for health-related quality of life (HRQoL). Examine HRQoL scores from 4 surveys representative of the noninstitutionalized US adult population for patterns related to age, gender, and mode of administration. We use data from the Joint Canada/United States Survey of Health (JCUSH; telephone survey), 2002 Medical Expenditure Panel Survey (MEPS; mail survey), National Health Measurement Study (NHMS; telephone survey), and US Valuation of the EuroQol EQ-5D Health States Survey (USVEQ; self-administered with interviewer present). We compare estimates from the EQ-5D, Visual Analog Scale, Health Utilities Index Mark 3, and general self-rated health stratified by age and gender. Scores were also regressed on age and gender within each survey and in a pooled analysis. We used 4939 subjects from JCUSH, 23,006 from MEPS, 3844 from NHMS, and 3878 from USVEQ. The majority of age and gender strata had instrument completion rates above 85%. Age- and gender-stratified estimates of HRQoL scores tended to be consistent when mode of administration (self- or interviewer-administered) was the same. Telephone administration yielded more positive HRQoL estimates than self-administration in older age groups. Older age groups and females reported lower HRQoL than younger age groups and males regardless of mode of administration. When choosing survey-collected HRQoL scores for comparative purposes, analysts need to take mode of administration into account.

1110 POSTER Management of anaemia in patient with cancer. Results of the F-ACT Study (French Anaemia Cancer Treatment)

Although utility-based algorithms have been developed for the Functional Assessment of Cancer Therapy (FACT), their properties are not well known compared with those of generic utility measures such as the EQ-5D. Our objective was to compare EQ-5D and FACT preference-based scores in cancer patients.A retrospective analysis was conducted on cross-sectional data collected from 472 cancer patients who completed both FACT-General and the EQ-5D. Preference-based scores were calculated by using published scoring functions for the EQ-5D (Dolan P. Modeling valuations for EuroQol health states. Med Care 1997;35:1095–108; Shaw JW, Johnson JA, Coons SJ. US valuation of the EQ-5D health states: development and testing of the D1 valuation model. Med Care 2005;43:203–20) and FACT (Dobrez D, Cella D, Pickard AS, et al. Estimation of patient preference-based utility weights from the Functional Assessment of Cancer Therapy-General. Value Health 2007;10:266–72; Kind P, Macran S. Eliciting social preference weights for Functional Assessment of Cancer Therapy-Lung health states. Pharmacoeconomics 2005;23:1143–53; Cheung YB, Thumboo J, Gao F, et al. Mapping the English and Chinese versions of the Functional Assessment of Cancer Therapy-General to the EQ-5D utility index. Value Health 2009;12:371–6). Scores were compared on the basis of clinical severity by using Eastern Cooperative Oncology Group performance status ratings by physicians and patients. Relative efficiency of each scoring function was examined by using ratios of F statistics.Mean scores for the overall cohort were lowest when using Kind and Macran's FACT UK societal algorithm (0.55, SD 0.09) and highest when using Dobrez et al.'s FACT US patient algorithm (0.83, SD 0.08). Mean difference scores associated with clinical severity, when extrapolated to quality-adjusted life-years (QALYs), had a range of 0.18 QALYs gained using FACT (Kind and Macran) to 0.45 QALYs gained using the EQ-5D (Dolan). However, relative efficiencies suggested that FACT (Kind and Macran) scores may provide greater statistical power to detect significant differences based on clinical severity.We found important differences in utilities scores estimated by each algorithm, with FACT-based algorithms tending to underestimate the QALY benefit compared with algorithms based on the EQ-5D. These differences highlight some of the challenges in using disease-specific preference-based measures for decision making despite potentially more relevant disease-specific content.

The Significance of Using US-Valued EQ-5D Health States for Comparative Effectiveness and Cost-Effectiveness Studies in US Populations

Two articles published in this issue, ‘‘A Comparison of EQ-5D Index Scores Derived from the US and UK Population-Based Scoring Functions’’ by Nan Luo and colleagues and ‘‘The Implications of Using US-Specific EQ-5D Preference Weights for Cost-Effectiveness Evaluation’’ by Katia Noyes and colleagues, substantially advance our understanding of the relative performance of USand UK-based EQ-5D preference scores. The study by Luo and others extends the previous work of its authors, who conducted the 2002 US valuation survey for the EQ-5D, using methods largely consistent with those of the 1993 UK valuation survey. Their new study compares the full complement of 243 EQ-5D health state scores predicted by the statistical models developed from the US and UK valuation surveys (both of which directly valued the same 42 common EQ-5D health states). Not surprisingly, like the authors’ earlier comparison of the directly valued health states, the US statistical model consistently predicted health state scores that were higher than those predicted by the UK model. Over the full set of EQ-5D health states, the difference in mean scores was 0.23, as compared with the 0.11 difference found for the smaller number of directly valued states in the earlier comparison. More notably, the new study found a mean difference in transitions between all pairs of health states of 0.25 for the US valuation model and 0.35 for the UK model: The range of all EQ-5D health state valuations in the US model was more compressed than in the UK model. The authors reasonably surmise that although incremental cost-effectiveness ratios (ICERs) calculated using the US model values would likely be less favorable than those using the UK model values, this result would depend on the nature of the condition under study, the severity of the health states, and the size of the health effect. Noyes and colleagues take another step and examine the differences in results between the USand UK-valued EQ-5D statistical models in a costeffectiveness analysis. Using the US values, they reanalyze data from a clinical trial comparing 2 alternative drug therapies (initial pramipexole v. levodopa) in patients with Parkinson disease, which originally used health state values from the UK EQ5D model (see references 15-17 in the article by Noyes and others). The comparative performance of the USand UK-valued EQ-5D models was consistent with the simulated results that Luo and others obtained: Measured over time, the USand UKspecific EQ-5D scores for patients with Parkinson disease followed similar trajectories, except that the US scores were higher on average. As in the simulation exercise, the range of scores using the US values was more compressed than that with the UK values. In particular, Noyes and others found greater differences between the US and UK estimates among subjects who reported problems with usual activities, pain/discomfort, or anxiety/depression than between the estimates for subjects not reporting these problems. As the authors conclude, the implications of the more compressed range of scores using the US valuation model are that the estimated 4-year gains in quality-adjusted life years (QALYs) of the experimental over the control therapy are less than half as large as those using the UK model, a much less favorable ICER ($108,000/QALY v. $43,000/QALY) and a lower probability that the experimental therapy is cost-effective at any dollar-per-QALY threshold. Taken together, these 2 studies offer insight into how valuations of health states based on the USand UK-valued EQ-5D statistical models compare From the Department of Health Policy, George Washington University School of Public Health and Health Services, Washington, DC.

Valuing cultural heritage in developing countries: comparing and pooling contingent valuation and choice modelling estimates

A substantial part of the United Nation’s World Heritage Sites (WHSs) can be found in developing countries, but many of them are in a bad state. Thus, there is a need to document the social benefits of these global goods in order to justify the costs of restoration and preservation programmes (RPPs). This study adds to the scarce literature on economic benefits of WHSs in developing countries, and reduces the need to perform very uncertain benefit transfers from European or US valuation studies. We apply Contingent Valuation (CV) and Choice Modelling (CM) to estimate the social benefits of RPPs for the My Son world cultural heritage site in Vietnam; both to foreign visitors and the local residents. We then compare the estimates from the CV and CM methods, and pool the results from the two methods. The results show that both CV and CM are suited to estimating the economic benefits of preserving cultural heritage of My Son. The two methods produce very similar results, which can be interpreted as a test of convergence validity. The pooling results give evidence to show that the CV and CM models have the same underlying preference structures. Thus, these valuation models can be successfully used in cost-benefit analyses to assess the benefits to cultural heritage of measures to reduce air pollution, soil erosion, climate change and other causes to deterioration of cultural heritage sites.

US Valuation of the EQ-5D Health States

The EQ-5D is a brief, multiattribute, preference-based health status measure. This article describes the development of a statistical model for generating US population-based EQ-5D preference weights. A multistage probability sample was selected from the US adult civilian noninstitutional population. Respondents valued 13 of 243 EQ-5D health states using the time trade-off (TTO) method. Data for 12 states were used in econometric modeling. The TTO valuations were linearly transformed to lie on the interval [-1, 1]. Methods were investigated to account for interaction effects caused by having problems in multiple EQ-5D dimensions. Several alternative model specifications (eg, pooled least squares, random effects) also were considered. A modified split-sample approach was used to evaluate the predictive accuracy of the models. All statistical analyses took into account the clustering and disproportionate selection probabilities inherent in our sampling design. Our D1 model for the EQ-5D included ordinal terms to capture the effect of departures from perfect health as well as interaction effects. A random effects specification of the D1 model yielded a good fit for the observed TTO data, with an overall R of 0.38, a mean absolute error of 0.025, and 7 prediction errors exceeding 0.05 in absolute magnitude. The D1 model best predicts the values for observed health states. The resulting preference weight estimates represent a significant enhancement of the EQ-5D's utility for health status assessment and economic analysis in the US.

Continuation and Reversal in US Valuation Ratios

We employ a two-regime, nonlinear model and more than a century of data to investigate the time series behavior of the S&P Composite price-dividends and price-earnings ratios. On average, the ratios display continuation fuelled by investor sentiment in bull markets but they adjust toward their long run equilibrium levels in bear markets. Impulse response functions that simulate the effect of a shock on the future evolution of the ratios exhibit the typical underreaction-overreaction time profile postulated in behavioral theories of stock returns. Our results indicate that market sentiment plays an important role in the short run but fundamentals dominate in the long run ensuring overall mean-reversion.

Valuing Health Impacts from Air Pollution in Europe

Health impacts make up asignificant portion of the damage costs fromair pollution. In lack of European valuationstudies on morbidity impacts, cost-benefitanalyses, transport and energy externalitystudies, and green accounting exercises inEurope have all used values from more than tenyear old US valuation studies. Results from anew Contingent Valuation study, using animproved version of the survey design of themost transferred US morbidity study, show thatrespiratory symptom days and asthma attacks arevalued lower in Norway than in the US.Correction were made for differences inpurchase power between the two countries, butthe US values are still expressed in 1986dollar values; indicating that the differencebetween the two estimates could be even higher.Thus, the practise of transferring US estimatesand only adjusting the values with the consumerprice index could lead to highly biased valuesin the Norwegian case. The difference betweenthe US and Norwegian values can be explained byimproved CV survey and sample design, differentpreferences in Norway compared to the US, anddifferent public health care systems. We do notknow if we can generalise the results from thisNorwegian study to the rest of Europe, but thestudy clearly illustrates the uncertainty intransferring results from one country toanother.