bluuebunny/crossref_metadata_2025 huggingface dataset:
Individual Utilities Are Inconsistent with Rationing Choices
Authors: Ubel Peter A. , Loewenstein George , Scanlon Dennis , Kamlet Mark
Published: March 2007

Objective. To test whether cost-effectiveness analysis and present methods of elic iting health condition "utilities" capture the public's values for health care rationing. Design. Two surveys of economics students. The first survey measured their utilities for three states of health, using either analog scale, standard gamble, or time tradeoff. The second survey measured their preferences, in paired rationing choices of the health states from the first survey and also compared with treatment of acutely fatal appendicitis. The rationing choices each subject faced were individualized according to his or her utility responses, so that the subject should have been indifferent between the two conditions in each rationing choice. Results. The analog-scale elicitation method produced significantly lower utilities than the time-tradeoff and standard-gam ble methods for two of the three conditions (p < 0.001 ). Compared with the rationing choices, all three utility-elicitation methods placed less value on the importance of saving lives and treating more severely ill people compared with less severely ill ones (p < 0.0001 ). The subjects' rationing choices indicated that they placed values on treating severely ill people that were tenfold to one-hundred-thousand-fold greater than would have been predicted by their utility responses. However, the subjects' rationing choices showed internal inconsistency, as, for example, treatments that were indicated to be ten times more beneficial in one scenario were valued as one hundred times more beneficial in other scenarios. Conclusions. The subjects soundly rejected the rationing choices derived from their utility responses. This suggests that people's an swers to utility elicitations cannot be easily translated into social policy. However, per son-tradeoff elicitations, like those given in our rationing survey, cannot be substituted for established methods of utility elicitation until they can be performed in ways that yield acceptable internal consistency. Key words: cost-effectiveness; utility assess ment ; rationing; medical ethics; health policy; standard gamble; time tradeoff; Oregon. (Med Decis Making 1996;16:108-116)
Statistical Comparison of ROC Curves from Multiple Readers
Authors: Swaving Marijke , Van Houwelingen Hans , Ottes Fenno P. , Steerneman Ton
Published: March 2007

Receiver operating characteristic (ROC) analysis is the commonly accepted method for comparing diagnostic imaging systems. In general, ROC studies are designed in such a way that multiple readers read the same images and each image is presented by means of two different imaging systems. Statistical methods for the comparison of the ROC curves from one reader have been developed, but extension of these meth ods to multiple readers is not straightforward. A new method of analysis is presented for the comparison of ROC curves from multiple readers. This method includes a non parametric estimation of the variances and covariances between the various areas under the curves. The method described is more appropriate than the paired t test, because it also takes the case-sample variation into account. Key words: ROC curves; ROC analysis; nonparametric estimation; area under the curve; comparison of ROC curves; EM algorithm. (Med Decis Making 1996;16:143-152)
A Criticism of Healthy-years Equivalents
Authors: Wakker Peter
Published: March 2007

The following questions describe the scope of this paper. When decision trees are used to analyze optimal decisions, should end nodes be evaluated on the basis of QALYs or on the basis of healthy-years equivalents? Which measures should be used in communications with others, e.g., patients? Which of these measures incorporate nsk attitudes, and which do not? It is demonstrated that the healthy-years equivalent measure does not stand scrutiny. Key words: utility; QALY; quality of life; healthy-years equivalent; standard gamble. (Med Decis Making 1996;16:207-214)
Heterogeneity in the Relationship between the Standard-gamble Utility Measure and Health-status Dimensions
Authors: Bult Jan Roelf , Bosch Johanna L. , Hunink Maria G.M.
Published: March 2007

The authors assessed the relationship between the standard-gamble utility measure and the RAND-36 health-status dimensions, taking into account possible heterogeneity among patients in the weights they assign to different health-status dimensions. A questionnaire including both measures was completed by 68 patients with symptomatic peripheral arterial disease. Conventional multiple regression analysis, assuming a ho mogeneous relationship for the total population between the standard-gamble utility and the RAND-36 health-status dimensions, demonstrated that only the dimension social functioning was significant (p < 0.05), which accounted for 10% of the variation. Assuming that the population consisted of two separate classes demonstrated superior representation of the data. Latent class analysis was used to estimate the unknown parameters and class memberships. In the first class, consisting of 65% of the patients, the relationship between the standard-gamble utility and the dimension general health perception was significant. The within-R2 was 12%. The second class represented 35% of the patients and showed significant coefficients for the dimensions social functioning and role limitations due to physical problems, which accounted for 80% of the variation. The overall percentage of variation explained by latent class analysis was 49%. The results suggest that patients with symptomatic peripheral arterial disease belong to a variety of classes, all with class-specific relationships between the standard-gamble utility and the RAND-36 health-status dimensions. Key words: health status measure; health utility measure; latent class analysis; heterogeneity. (Med Decis Making 1996; 16:226-233)
Long-term Care Residents' Preferences for Health States on the Quality of Well-Being Scale
Authors: Hays Ron D. , Siu Albert L. , Keeler Emmett , Marshall Grant N. , Kaplan Robert M. , Simmons Sandra , El Mouchi Daryl , Schnelle John F.
Published: March 2007

The Quality of Well-Being Scale (QWB) quantifies health-related quality of life with a single number that represents community-based preferences for combinations of symptom/problem complexes, mobility, physical activity, and social activity. The aim of this study was to compare preferences of a long-term care population with those of the general population, determine whether preferences vary by the age of the hypo thetical (target) person depicted in the health-state case description, and derive weights for new symptom/problem complexes of particular relevance to frail, older individuals. A sample of 38 female and 12 male long-term care residents with an average age of 86 years was asked to rate health-state scenarios that combined the four health domains of the QWB. This sample rated quality of life 0.10 units lower on average (on a 0-1 scale) than did the general population sample from which the QWB preferences were originally developed. Ratings of the same health state for younger versus older target persons did not differ significantly (all p values > 0.05 for t statistics). Weights derived for 11 new symptom/problem complexes were: disturbed sleep (-0.252), sit-to-stand requires maximal effort (-0.259), lonely (-0.265), walking a short distance causes extreme fatigue (-0.273), agitated (-0.284), hallucinating (-0.355), incontinent (-0.359), unable to control one's behavior (-0.360), urinary catheter (-0.374), restrained in bed or chair (-0.374), and feeding tube through the nose or stomach (-0.402). These new weights increase the relevance of the QWB for cost-utility evaluations of health interventions for long-term care residents. Key words: health state preferences; long-term care; patient preferences; Quality of Well-Being Scale; quality of life; age factors. (Med Decis Making 1996;16:254-261)
The Psychology of Good Judgment
Authors: Gigerenzer Gerd
Published: March 2007

Mind and environment evolve in tandem—almost a platitude. Much of judgment and decision making research, however, has compared cognition to standard statistical models, rather than to how well it is adapted to its environment. The author argues two points. First, cognitive algorithms are tuned to certain information formats, most likely to those that humans have encountered during their evolutionary history. In par ticular, Bayesian computations are simpler when the information is in a frequency format than when it is in a probability format. The author investigates whether fre quency formats can make physicians reason more often the Bayesian way. Second, cognitive algorithms need to operate under constraints of limited time, knowledge, and computational power, and they need to exploit the structures of their environments. The author describes a fast and frugal algorithm, Take The Best, that violates standard principles of rational inference but can be as accurate as sophisticated "optimal" mod els for diagnostic inference. Key words: Bayes' theorem; bounded rationality; infor mation format; probabilistic reasoning; satisficing; training; medical education. (Med Decis Making 1996;16:273-280)
Predicting In-hospital Mortality for Stroke Patients
Authors: Iezzoni Lisa I. , Shwartz Michael , Ash Arlene S. , Mackiernan Yevgenia D.
Published: March 2007

Objective: To see whether severity-adjusted predictions of likelihoods of in-hospital death for stroke patients differed among severity measures. Methods: The study sam ple was 9,407 stroke patients from 94 hospitals, with 916 (9.7%) in-hospital deaths. Probability of death was calculated for each patient using logistic regression with age-sex and each of five severity measures as the independent variables: admission MedisGroups probability-of-death scores; scores based on 17 physiologic variables on admission; Disease Staging's probability-of-mortality model; the Severity Score of Pa tient Management Categones (PMCs); and the All Patient-Refined Diagnosis Groups (APR-DRGs). For each patient, the odds of death predicted by the severity measures were compared. The frequencies of seven clinical indicators of poor prognosis in stroke were examined for patients with very different odds of death predicted by different severity measures. Odds ratios were considered very different when the odds of death predicted by one severity measure was less than 0.5 or greater than 2.0 of that pre dicted by a second measure. Results: MedisGroups and the physiology scores pre dicted similar odds of death for 82.2% of the patients. MedisGroups and PMCs disa greed the most, with very different odds predicted for 61.6% of patients. Patients viewed as more severely ill by MedisGroups and the physiology score were more likely to have the clinical stroke findings than were patients seen as sicker by the other severity measures. This suggests that MedisGroups and the physiology score are more clinically credible. Conclusions: Some pairs of severity measures ranked over 60% of patients very differently by predicted probability of death. Studies of seventy-adjusted stroke outcomes may produce different results depending on which seventy measure is used for risk adjustment. Key words: seventy; risk adjustment; stroke; in-hospital deaths; mortality rates. (Med Decis Making 1996;16:348-356)
Assigning Values to Intermediate Health States for Cost-Utility Analysis
Authors: Cohen Brian J.
Published: March 2007

Cost-utility analysis (CUA) was developed to guide the allocation of health care re sources under a budget constraint. As the generally stated goal of CUA is to maximize aggregate health benefits, the philosophical underpinning of this method is classic utilitarianism. Utilitarianism has been criticized as a basis for social choice because of its emphasis on the net sum of benefits without regard to the distribution of benefits. For example, it has been argued that absolute priority should be given to the worst off when making social choices affecting basic needs. Application of classic utilitarianism requires use of strength-of-preference utilities, assessed under conditions of certainty, to assign quality-adjustment factors to intermediate health states. The two methods commonly used to measure strength-of-preference utility, categorical scaling and time tradeoff, produce rankings that systematically give priority to those who are better off. Alternatively, von Neumann-Morgenstern utilities, assessed under conditions of un certainty, could be used to assign values to intermediate health states. The theoretical basis for this would be Harsanyi's proposal that social choice be made under the hypothetical assumption that one had an equal chance of being anyone in society. If this proposal is accepted, as well as the expected-utility axioms applied to both indi vidual choice and social choice, the preferred societal arrangement is that with the highest expected von Neumann-Morgenstern utility. In the presence of nsk aversion, this will give some priority to the worst-off relative to classic utilitarianism. Another approach is to raise the values obtained by time-tradeoff assessments to a power a between 0 and 1. This would explicitly give priority to the worst off, with the degree of priority increasing as a decreases. Results could be presented over a range of a. The results of CUA would then provide useful information to those holding a range of phil osophical points of view. Key words: cost-utility analysis; strength-of-preference utility; von Neumann-Morgenstern utility; interpersonal comparisons of utility; health care rationing; utilitarianism. (Med Decis Making 1996;16:376-385)
Test-indication Curves
Authors: Bernstein Joseph
Published: March 2007

Test-indication curves (TiCs) are tools for determining whether a test is indicated for a given patient. They apply the threshold approach of Pauker and Kassirer in graphic form. These curves are composed of two parts: the raw curve, which plots posttest probability versus pretest probability (given values for specificity and sensitivity); and the final curve, in which three straight lines are added to the raw curve by the clinician to generate a TIC for a given treatment threshold. In the final curve, the complete range of pretest probability is segregated into three zones, corresponding to the three groups described by Pauker and Kassirer: those patients in whom disease is assumed to be present and who are thus best treated empirically; at the other extreme, those who require neither testing nor treatment; and, finally, those in the middle, for whom the test is indicated, since the decision to treat would be based on the test result. Thus the clinician could consult the TIC and determine with certainty whether the test should be employed for a given patient. It also could be modified with ease for a different patient, with a different set of threshold values. TICs provide a complete, visual inter pretation of a test's diagnostic power, in the context of a given treatment threshold. They foster an intuitive comprehension of Pauker and Kassirer's method, and offer the clinician a facile means to prove that a test is indicated in a given setting. By promoting the use of exactly those tests that are indicated, TICs can help spare the patient the cost, burden, and risk of unnecessary testing, and help spare the physician the cost, burden, and risk of interpreting inconclusive test results. Key words: test-indication curves; treatment thresholds; laboratory tests. (Med Decis Making 1997;17:103-106)
Primer on Medical Decision Analysis: Part 1—Getting Started
Authors: Detsky Allan S. , Naglie Gary , Krahn Murray D. , Naimark David , Redelmeier Donald A.
Published: March 2007

This paper is Part 1 of a five-part series covering practical issues in the performance of decision analysis. The intended audience is individuals who are learning how to perform decision analyses, not just read them. The series assumes familiarity with the basic concepts of decision analysis. It imparts many of the recommendations the authors have learned in teaching a one-semester course in decision analysis to graduate students. Part 1 introduces the topic and covers questions such as choosing an appropriate question, determining the tradeoff between accuracy and simplicity, and deciding on a time frame. Key words: decision analysis; expected value; utility; sensitivity analysis; decision trees; probability. (Med Decis Making 1997;17:123-125)
Primer on Medical Decision Analysis: Part 2—Building a Tree
Authors: Detsky Allan S. , Naglie Gary , Krahn Murray D. , Redelmeier Donald A. , Naimark David
Published: March 2007

This part of a five-part series covering practical issues in the performance of decision analysis outlines the basic strategies for building decision trees. The authors offer six recommendations for building and programming decision trees. Following these six recommendations will facilitate performance of the sensitivity analyses required to achieve two goals. The first is to find modeling or programming errors, a process known as "debugging" the tree. The second is to determine the robustness of the qualitative conclusions drawn from the analysis. Key words: decision analysis; expected value; utility; sensitivity analysis; decision trees; probability. (Med Decis Making 1997;17: 126-135)
Primer on Medical Decision Analysis: Part 3—Estimating Probabilities and Utilities
Authors: Naglie Gary , Krahn Murray D. , Naimark David , Redelmeier Donald A. , Detsky Allan S.
Published: March 2007

This paper describes how to estimate probabilities and outcome values for decision trees. Probabilities are usually derived from published studies, but occasionally are derived from existing databases, primary data collection, or expert judgment. Outcome values represent quantitative estimates of the desirability of the outcome states, and are often expressed as utility values between 0 and 1. Utility values for different health states can be derived from the published literature, from direct measurement in appropriate subjects, or from expert opinion. Methods for assigning utilities to complex outcome states are described, and the concept of quality-adjusted life years is introduced. Key words: decision analysis; expected value; utility; sensitivity analysis; decision trees; probability. (Med Decis Making 1997;17:136-141)
Primer on Medical Decision Analysis: Part 4-Analyzing the Model and Interpreting the Results
Authors: Krahn Murray D. , Naglie Gary , Naimark David , Redelmeier Donald A. , Detsky Allan S.
Published: March 2007

This paper is the fourth of a five-part series that describes the principles of construction and evaluation of valid decision models. In this review, the authors describe the key principles of detecting and eliminating structural and programming errors in decision trees (debugging). In addition, they offer guidelines to facilitate the interpretation of analytic results of decision models. Key words: decision analysis; expected value; utility ; sensitivity analysis; decision trees; probability. (Med Decis Making 1997;17:142- 151)
Deciding Eligibility for Transplantation When a Donor Kidney Becomes Available
Authors: Hornberger John , Ahn Jae-Hyeon
Published: March 2007

The expectation of transplant success for some patient/donor-kidney matches can be so low that transplantation is not considered an option. The issue may be framed as deciding the minimum expectation of transplant success that would justify a patient's eligibility for transplantation with an available donor kidney. If the minimum is set too high, the patient will be eligible for very few donor kidneys and will wait excessively for transplantation. If the minimum is set too low, the patient has a greater risk of graft failure once transplantation has been done. A decision model calculates the minimum predicted one-year graft survival rate that would determine eligibility for an available donor kidney, with the goal of maximizing quality-adjusted life expectancy. The minimum predicted one-year graft survival rate depends on the patient's health and demographic characteristics and attitudes about quality of life with kidney-replacement therapies. Graft survival rates and quality-adjusted life expectancies may increase by as much 6.7% and 1.6 months, respectively, with only a slight increase (<0.4 months) in the quality-adjusted waiting time until transplantation. Key words: transplantation; health services research; decision analyses; rationing. (Med Decis Making 1997;17: 160-170)
The Use of Confidence Intervals for Individual Utilities:
Authors: Roest Frits H.J. , Eijkemans Marinus J.C. , Van Der Donk Jos , Levendag Peter C. , Meeuwis Cees A. , Schmitz Paul I.M. , Habbema J. Dik F.
Published: March 2007

This paper discusses the use of confidence intervals for utility measurements. Classic test theory is applied to estimate confidence intervals for utilities. The theory is enhanced to calculate confidence areas for combined utilities and confidence bands for the threshold line. As an example it is shown that, if confidence intervals are taken into account, the implied preferred treatment of T3-larynx carcinoma patients is uncertain for a wide range of utilities, considering the mediocre reliability of most methods of utility assessment. This implies that although utility measurement and formal decision analysis can be a useful way to look at the decision problem, ambiguity, which must be resolved by other means, will often remain. Key words: utility theory; utility measurement; confidence intervals. (Med Decis Making 1997;17:285-291)
Incorporating Risk Attitude into Markov-process Decision Models:
Authors: Cher Daniel J. , Miyamoto John , Lenert Leslie A.
Published: March 2007

Most decision models published in the medical literature take a risk-neutral perspective. Under risk neutrality, the utility of a gamble is equivalent to its expected value and the marginal utility of living a given unit of time is the same regardless of when it occurs. Most patients, however, are not risk-neutral. Not only does risk aversion affect decision analyses when tradeoffs between short- and long-term survival are involved, it also affects the interpretation of time-tradeoff measures of health-state utility. The proportional time tradeoff under- or overestimates the disutility of an inferior health state, depending on whether the patient is risk-seeking or risk-averse (it is unbiased if the patient is risk-neutral). The authors review how risk attitude with respect to gambles for survival duration can be incorporated into decision models using the framework of risk-adjusted quality-adjusted life years (RA-QALYs). They present a simple extension of this framework that allows RA-QALYs to be calculated for Markov-process decision models. Using a previously published Markov-process model of surgical vs expectant treatment for benign prostatic hypertrophy (BPH), they show how attitude towards risk affects the expected number of QALYs calculated by the model. In this model, under risk neutrality, surgery was the preferred option. Under mild risk aversion, expectant treatment was the preferred option. Risk attitude is an important aspect of preferences that should be incorporated into decision models where one treatment option has up-front risks of morbidity or mortality. Key words : risk attitude; Markov models; patient preferences; quality-adjusted life years. (Med Decis Making 1997;17:340-350)
Construct Validities of the Quality of Well-Being Scale and the MOS-HIV-34 Health Survey for HIV-infected Patients
Authors: Hughes Tom E. , Kaplan Robert M. , Coons Stephen Joel , Draugalis Jolaine R. , Johnson Jeffrey A. , Patterson Thomas L.
Published: March 2007

This research assessed the construct validities of two health-related quality-of-life in struments: the Quality of Well-Being Scale (QWB) and the Medical Outcomes Study 34-item HIV Health Survey (MOS-HIV-34). A sample of 100 adult male, HIV-infected patients, across six HIV disease classifications, was used as subjects. Four convergent validity measures of health-related quality of life were used: CD4 cell counts, beta-2 microglobulin levels, disease classification, and age. All convergent validity measures were significant for the QWB. Forty percent of the convergent validity com parisons with the MOS-HIV-34 were statistically significant. Because the two measures provide different perspectives on health-related quality of life, both instruments appear to be useful in measuring health-related quality of life in this patient population. Key words: HIV; quality of life; quality of well-being scale; construct validity. (Med Decis Making 1997;17:439-446)
The Economics of Treatment for Infants with Respiratory Distress Syndrome
Authors: Neil Nancy , Sullivan Sean D. , Lessler Daniel S.
Published: March 2007

Objectives. To define clinical outcomes and prevailing patterns of care for the initial hospitalization of infants at greatest risk for respiratory distress syndrome (RDS); to estimate direct medical care costs associated with the initial hospitalization; and to introduce and demonstrate a simulation technique for the economic evaluation of health care technologies. Method. Clinical outcomes and usual-care algorithms were determined for infants with RDS in three birthweight categories (500-1,000 g; >1,000- 1,500 g; and >1,500 g) using literature- and expert-panel-based data. The experts were practitioners from major U.S. hospitals who were directly involved in the clinical care of such infants. Using the framework derived from the usual care patterns and outcomes, the authors developed an itemized "micro-costing" economic model to sim ulate the costs associated with the initial hospitalization of a hypothetical RDS patient. The model is computerized and dynamic; unit costs, frequencies, number of days, probabilities and population multipliers are all variable and can be modified on the basis of new information or local conditions. Aggregated unit costs are used to estimate the expected medical costs of treatment per patient. Results. Expected costs of initial hospitalization per uncomplicated surviving infant with RDS were estimated to be $101,867 for 500-1,000 g infants; $64,524 for >1,000-1,500 g infants; and $27,224 for >1,500 g infants. Incremental costs of complications among survivors were esti mated to be $22,155 (500-1,000 g); $11,041 (>1,000-1,500 g); and $2,448 (>1,500 g). Expected costs of initial hospitalization per case (including non-survivors) were $100,603; $72,353; and $28,756, respectively. Conclusions. An itemized model such as the one developed here serves as a benchmark for the economic assessment of treatment costs and utilization. Moreover, it offers a powerful tool for the prospective evaluation of new technologies or procedures designed to reduce the incidence of, severity of, and/or total hospital resource use ascribed to RDS. Key words: respiratory distress syndrome; low birthweight; technology assessment; economics; costs. (Med Decis Making 1998;18:44-51)
What Attitudes and Beliefs Underlie Patients' Decisions about Participating in Chemotherapy Trials?
Authors: Sutherland Heather J. , da Cunha Raquel , Lockwood Gina A. , Till James E.
Published: March 2007

The theory of reasoned action, which postulates that personal attitudes and external social influences predict intentions to undertake a behavior, was used as a conceptual framework for developing a questionnaire to elicit beliefs and attitudes associated with the decision to participate in a hypothetical cancer chemotherapy trial. After completing the questionnaire, two-thirds of the 150 respondents indicated they would enroll in such a trial if it were available. Considerable variation existed in both "universal" and "trial- specific" beliefs and attitudes underpinning their intentions. A substantial amount of the variance in "intention" to participate was explained by "attitude" alone (75%). So cial influences, although statistically significant, made a mere 1% additional contribu tion. One interpretation is that subjective expected-utility theory, which essentially pre dicts beliefs or "attitude," is a better model. The authors conclude that both theories may be criticized regarding how well they capture the rationality and nuances of de cision behavior. Key words: attitudes; beliefs; clinical trials; oncology. (Med Decis Mak ing 1998;18:61-69)
Physicians' Diagnostic Judgments and Treatment Decisions for Acute Otitis Media in Children
Authors: González-Vallejo Claudia , Sorum Paul C. , Stewart Thomas R. , Chessare John B. , Mumpower Jeryl L.
Published: March 2007

Physicians' diagnoses of acute otitis media (AOM) and their treatment choices were investigated using judgment and decision-making analyses. Thirty-two pediatricians in the Albany, New York, area provided probability judgments of the presence of AOM and made treatment decisions for 32 patient vignettes, each described in terms of historical and examination variables. Their probability judgments were well predicted by linear combinations of the patient variables (R2s ranged from 0.76 to 0.97). Information about the observed condition of the eardrum proved to be most critical to the physicians' diagnoses. They demonstrated good levels of agreement on diagnoses. They varied, however, in their tendencies to treat with amoxicillin rather than another antibiotic. Case vagueness was related to the rate of antibiotic treatment. The rate of antibiotic treatment was higher for vague than for non-vague cases when the mean judged probability of AOM was low. In combination, the findings highlight the importance of performing and interpreting ear examinations and the role that consistent training may have in improving management of AOM.
Implicit Discount Rates of Vascular Surgeons in the Management of Abdominal Aortic Aneurysms
Authors: Enemark Ulrika , Lyttkens Carl H. , Troëng Thomas , Weibull Henrik , Ranstam Jonas
Published: March 2007

A growing empirical literature has investigated attitudes towards discounting of health benefits with regard to social choices of life-saving and health-improving measures and individuals' time preferences for the management of their own health. In this study, the authors elicited the time preferences of vascular surgeons in the context of management of small abdominal aortic aneurysms, for which the choice between early elective surgery and watchful waiting is not straightforward. They interviewed 25 of a random sample of 30 Swedish vascular surgeons. Considerable variation in the time preferences was found in the choices between watchful waiting and surgical intervention among the otherwise very homogeneous group of surgeons. The discount rates derived ranged from 5.3% to 19.4%. The median discount rate (10.4%) is similar to those usually reported for social choices concerning life-saving measures. The surgeons who were employed in university hospitals had higher discount rates than did their colleagues in county and district hospitals.
Sequence Effects, Health Profiles, and the QALY Model
Authors: Krabbe Paul F. M. , Bonsel Gouke J.
Published: March 2007

The authors conducted an experiment to determine whether the sequence of presentation of states in a health profile would affect the valuations assigned to them. The empirical task was part of a large standardized experiment involving 104 students. Thirteen health states were valued using two variations of the time-tradeoff method. At the group level, a small but distinct overall effect of the sequence of the tradeoffs was detected after accounting for discounting effects. The respondents were not preference-indifferent concerning the sequence of health states presented. Detailed analysis at the individual level indicated that the overall sequence effect was attributable to two groups of respondents who were sensitive to the sequence of events. One small group, referred to as “best-things-first” respondents, preferred the best years first; the other group, classified as “happy-end” respondents, preferred the reverse sequence. The majority of the respondents, however, were indifferent to the sequence. These results suggest that 1) in valuation experiments involving the time-tradeoff method and 2) in applying valuation results to the evaluation of real-life health consequences, a varying lifetime health profile may not be regarded as simply a chain of independent separately valued and discounted QALY periods. Even elementary valuation tasks cannot safely assume ignorance of prognosis, as the additive utility independence assumption of the QALY model does not hold. The sequence effect at least supplements the conventional general time-preference concept, and specific strategies are suggested to disentangle quantitatively the sequence effect and the time-preference effect.
Effect of an Explicit Decision-Support Tool on Decisions to Prescribe Antibiotics for Sore Throat
Authors: McIsaac Warren J. , Goel Vivek
Published: March 2007

Studies of scoring rules for sore throat have failed to show that they lower antibiotic prescription rates. The authors studied the effect of an explicit decision-support tool, incorporating a modified score, on antibiotic-prescription decisions. Four hundred and fifty family physicians received an information package, a score card, and a recording form to use during one sore-throat encounter. The physicians randomly received either a control form or an intervention form that required them to interact with the score during the clinical recording process. There was a trend towards a reduction in antibiotic prescriptions (21%, p = 0.09) in the physicians using the intervention form. A greater reduction (45%, p = 0.06) was observed for patients whose probabilities of infection with group A streptococcus were low. Sore-throat-scoring rules may reduce unnecessary antibiotic prescriptions if physicians are specifically cued to use them during clinical encounters and appropriate management responses are linked to score estimates for the likelihood of group A streptococcus infection.
Using a Treatment-tradeoff Method to Elicit Preferences for the Treatment of Locally Advanced Non-Small-cell Lung Cancer
Authors: Brundage Michael D. , Davidson Judith R. , Mackillop William J. , Feldman-Stewart Deb , Groome Patti
Published: March 2007

The study was designed to evaluate a treatment-tradeoff method for its potential in helping lung cancer patients make treatment decisions. A treatment-tradeoff interview was conducted to determine how patients weighed potential survival benefits against the potential toxicities of different treatment options: 1) low-dose versus high-dose radiotherapy, and 2) high-dose radiotherapy versus combination chemo-radiotherapy. Fifty-six patients who had experienced cancer and 20 clinic staff participated; twenty of these participants repeated the interview in an assessment of response consistency. The treatment-tradeoff method proved feasible: all staff and 53 of the 56 patients were able to complete the process. A wide range of threshold scores across participants was observed for both tradeoffs. Sixty percent of the patients would accept the more toxic combination therapy over high-dose radiotherapy if the former offered a 10% absolute improvement in three-year survival. The method also proved reliable: test-retest correlations were high (τ ranged from 0.7 to 0.87 and r from 0.82 to 0.94) and test-retest mean score differences were low (1.3-4.2). The most clinically useful mea sure of consistency was a "preference consistency" index, which revealed that most patients declared the same treatment preference at test and retest. The authors conclude that, while there is great interindividual variability in willingness to accept aggressive treatments for lung cancer, patients' values can be consistently elicited with the tradeoff method. The method has potential for clinical application in decision making and for health-care policy development. Key words: treatment tradeoffs; patient decision making; lung cancer; policy. (Med Decis Making 1998;18:256-267)
Assessment of the Time-tradeoff Val ues for Prophylactic Mastectomy of Women with a Suspected Genetic Predisposition to Breast Cancer
Authors: Unic Ivana , Stalmeier Peep F.M. , Verhoef Lia C.G. , Van Daal Willem A.J.
Published: March 2007

Background. Female carriers of the breast-cancer-susceptibility genes BRCA1 and BRCA2 are at high risk for breast cancer (85%). They face the choice between pro phylactic mastectomy (PM) and breast cancer screening. For this treatment choice, a shared-decision-making program was developed. In this program, the time tradeoff (TTO) was used to assess preferences for PM. Purpose. Assessment of the feasibility, constant proportional tradeoff, and reliability of using the TTO for this purpose. Meth ods. Fifty-four women suspected to carry the BRCA1/2 mutation were provided with comprehensive relevant information. Their preferences for PM were assessed on two occasions. Discrepancies between preferences indicated by the two tests were re solved by testing a third time. The preferences assessed on the last occasion were used for individual decision analyses. In order to test constant proportional tradeoff, the TTO consisted of four items with different numbers of life years. Results. Forty- two women (78%) completed the TTO twice and nine women (17%) performed the test a third time. Three women (5%) completed the TTO only once. The mean TTO value for PM at the last replication was 0.69 (SD = 0.30). Violations of constant pro portional tradeoff were significant: the largest tradeoffs were recorded for the shortest durations. Pearson's correlation coefficient between the TTO values for the two last sessions was 0.96. Conclusion. Assessment of individual preferences by the TTO in this patient group is feasible and reliable. Therefore, the TTO can be used in clinical settings to elicit treatment preferences of women proven or suspected to have a ge netic predisposition to breast cancer. Key words: shared decision making; breast can cer ; prophylactic mastectomy; preference assessment; time tradeoff; genetic predis position. (Med Decis Making 1998;18:268-277)
More Evidence of the Plateau Effect
Authors: Pinto-Prades Jose-Luis , Lopez-Nicolás Angel
Published: March 2007

The purpose of this study was to test the existence of the plateau effect at the social level. The authors tried to confirm the preliminary conclusion that people may not be willing to trade off any longevity to improve the health state of a large number of people if the health states are mild enough. They tested this assumption using the person- tradeoff technique. They also used a parametric approach and a nonparametric ap proach to study the relationship between individual and social values. Results show the existence of the plateau effect in the context of resource allocation. Furthermore, with the nonparametric approach, a plateau effect in the middle part of the scale was also observed, suggesting that social preference may not be directly predicted from individual utilities. The authors caution against the possible framing effects that may be present in these kinds of questions. Key words: person tradeoffs; social prefer ences ; utility assessments; plateau effect. (Med Decis Making 1998;18:287-294)
Text-to-algorithm Conversion to Facilitate Comparison of Competing Clinical Guidelines
Authors: Barak Nurit , Margolis Carmi Z. , Gottlieb Lawrence K.
Published: March 2007

This study aimed to test the usefulness and reliability of text-to-algorithm conversion in comparing competing clinical guidelines and defining their differences. Two pairs of competing guidelines for measles immunization, published in 1989 and 1994, were analyzed and compared. Five categories of differences were detected: differences in recommendations, excluded elements, logical inconsistencies, nonspecific phrases, and approaches to contraindications. On a scale of 0-10 (where identical = 10), the overall comparison scores were 6.01 for the guidelines published in 1989 and 5.54 for the guidelines published in 1994. Text-to-algorithm conversions performed by three different persons on the 1989 guidelines were compared and found similar. Text-to- algorithm conversion is an important step in facilitating comparison of competing guide lines. It has the potential to assist in making rational and systematic choices between competing guidelines before actual field testing takes place. Physicians can use it to analyze and to learn a prose clinical guideline, to critique existing guidelines, and to simulate hypothetical patients for teaching and evaluating clinical management. Key words: medical decision making; clinical guidelines; clinical algorithms; health services evaluation; semantic analysis; measles immunization. (Med Decis Making 1998;18: 304-310)
Validation of Models for Predicting the Use of Health Technologies
Authors: Scalon João D. , Freire Sergio M. , Cunha Tacio A.
Published: March 2007

Validation must be carried out before a model can be used confidently as a tool of managerial decision making in health care. The authors describe a bootstrap approach to validating models for predicting the utilization of four technologies used in neonatal care: measurement of blood gases (gasometry), the oxygen hood, continuous positive airway pressure (CPAP), and mechanical ventilation. These models were fitted by stepwise multiple linear regression from 20 prognostic covariates of 193 neonates. One hundred bootstrap samples were generated to validate the choices of covariates in the models based on their frequencies of selection. This approach validated the models for the oxygen hood and CPAP. The regression coefficients and standard deviations for the CPAP and oxygen hood models were estimated using 200 additional bootstrap samples. A close agreement between stepwise and bootstrap estimates was observed for both models. These results suggest that bootstrap can be useful for validating models for predicting the utilization of health technologies Key words: ne onatal intensive care, forecasting; health facility planning; health technology; bootstrap; model validation; regression analysis; linear models. (Med Decis Making 1998;18: 311-319)
Nonparametric Willingness-to-pay Measures and Confidence Statements
Authors: Tambour Magnus , Zethraeus Niklas
Published: March 2007

Willingness to pay (WTP) for a health care program can be estimated in contingent valuation (CV) studies by a nonparametric approach. The nonparametric approach is free from distributional assumptions, which is a strength compared with parametric regression-based approaches. However, using a nonparametric approach it is not clear how to obtain confidence statements for WTP estimates, for example, when testing hypotheses regarding differences in mean WTP for different subsamples. The authors propose a procedure that allows statistical testing and confidence interval estimation by employing bootstrap techniques. The method is easy to implement and has low computational costs with modern personal computers. The method is applied to data from a CV study where the WTP for hormone replacement therapy was investigated. The mean WTP was estimated for the full sample and separately for women with mild and severe menopausal symptoms. Using the proposed method, the mean WTP was significantly higher in the group with severe symptoms. Key words: bootstrap; economic evaluation; hormone replacement therapy; nonparametric; willingness to pay. (Med Decis Making 1998;18:330-336)
Patients' Utilities for Cancer Treatments
Authors: Jansen Sylvia J.T. , Stiggelbout Anne M. , Wakker Peter P. , Vliet Vlieland Thea P.M. , Leer Jan-Willem H. , Nooy Marianne A. , Kievit Job
Published: March 2007

Objective. Temporary health states cannot be measured in the traditional way by means of techniques such as the time tradeoff (TTO) and the standard gamble (SG), where health states are chronic and are followed by death. Chained methods have been developed to solve this problem. This study assesses the feasibility of a chained TTO and a chained SG, and the consistency and concordance between the two meth ods. Patients and methods. Seventy female early-stage breast cancer patients were interviewed. In using both chained methods, the temporary health state to be evaluated was weighed indirectly with the aid of a temporary anchor health state. The patients were asked to evaluate their actual health states, a hypothetical radiotherapy scenario, and a hypothetical chemotherapy scenario. Results. Sixty-eight patients completed the interview. The use of the anchor health state yielded some problems. A significant difference between the means of the TTO and the SG was found for the anchor health state only. For the other health states, the results were remarkably close, because the design avoided some of the bias effects in traditional measurements. Conclusion. The feasibility and the consistency of the chained procedure were satisfactory for both methods. The problems regarding the anchor health state can be solved by adapting the methods and by the use of a carefully chosen anchor health state. The chained method avoids biases present in the conventional method, and thereby the TTO and the SG may be reconciled. Moreover, there are several psychological advantages to the method, which makes it useful for diseases with uncertain prognoses. Key words: utility assessment; time tradeoff; standard gamble; breast cancer; chemotherapy; ra diotherapy. (Med Decis Making 1998;18:391-399)
Time-tradeoff Values and Standard-gamble Utilities Assessed during Telephone Interviews versus Face-to-face Interviews
Authors: Van Wijck Esther E. E. , Bosch Johanna L. , Hunink Maria G. M.
Published: March 2007

The purpose of this study was to compare time-tradeoff values and standard-gamble utilities obtained during telephone interviews with those obtained through face-to-face interviews. Sixty-five patients with peripheral arterial occlusive disease completed both interviews. One week prior to the telephone interview, the patients received by mail a questionnaire in which the value and utility measures were presented in writing. The face-to-face interviews used the same questions, but the interviewer used visual aids. The mean time-tradeoff values were 0.84 (SD 0.20) vs 0.86 (SD 0.17) for the telephone and face-to-face interviews, respectively (p = 0.31). The mean standard-gamble utilities were 0.93 (SD 0.16) vs 0.92 (SD 0.17) for the telephone and face-to-face interviews, respectively (p = 0.26). In conclusion, telephone interviews yield similar time-tradeoff values and standard-gamble utilities compared with face-to-face interviews, suggesting that telephone interviews can replace face-to-face interviews. Key works: utility as sessment ; time tradeoff; standard gamble; telephone interviews. (Med Decis Making 1998;18:400-405)
Attitudes of Obstetricians and Gynecologists toward Hormone Replacement Therapy
Authors: Baron Jonathan , Holzman Gerald B. , Schulkin Jay
Published: March 2007

Objective. To determine the attitudes of obstetricians and gynecologists toward hor mone replacement therapy (HRT), and the beliefs and intuitions that affected those attitudes. Design. A questionnaire was sent to 1,000 gynecologists in the United States; 328 replies were received. The questionnaire asked about effects of HRT, practices concerning HRT, and decisions in hypothetical scenarios. Results. The re spondents strongly favored HRT, and they were well informed about its effects on osteoporosis, cardiovascular disease, and breast cancer. They were aware of conflict ing findings concerning breast cancer. The strength of their recommendation of HRT was sensitive to patient differences in risk factors. The respondents also showed four biases hypothesized to cause resistance to HRT: omission bias (more concern about harmful acts than harmful omissions); proportionality bias (attention to relative risk rather than risk differences); naturalness bias (preference for the natural); and ambi guity (avoiding options with missing information). Proportion bias, naturalness bias, and (weakly) omission bias were related to less favorable attitudes toward HRT. Con clusion. Although specialists are highly favorable toward HRT in general, some neg ativity toward HRT may result from decision biases. Key words: hormone replacement; estrogen; decision making; biases. (Med Decis Making 1998;18:406-411)