bluuebunny/crossref_metadata_2025 huggingface dataset:
The Politics of Popular Culture: A Case Study
Authors: Carey James W.
Published: March 2007

The real issue is the distortion of life by the means of communication, the abstraction of culture from time and place. Television everywhere consists largely of messages from nowhere, aimed at no one, and presenting nothing. And yet we gull ourselves into believing we are being entertained and informed.
Fieldwork and Communication Research: Some Anthropological Cautions
Authors: Farnsworth Kent A.
Published: March 2007

Somewhere underneath the prose of social science lies some human contact. Before the clatter of the typewriter begins, some person (a social science researcher) collaborates with another person (variously called subject, respondent, or informant) to create a social relationship within which an exchange of information occurs (Agar, 1980: 1).
Community and Class Struggle: Problems in Methodology
Authors: Tomaselli Keyan G. , Tomaselli Ruth E.
Published: March 2007

This article was written in collaboration with P. Eric Louw, Ansuya Chetty and students of the CCSU. It reflects many points raised during the popular writing workshop organized by the Centre for Adult and Continuing Education of the University of Western Cape. The workshop was part of the 1986 Association for Sociology in Southern Africa Conference.
Media Dependency, Bubonic Plague, and the Social Construction of the Chinese Other
Authors: Power J. Gerard
Published: March 2007

There is no other city in Europe or America that has met the peril of plague in the way San Francisco has done, there is no place where press and public have so persistently fought the necessary measures in the desire to prove that plague did not exist among them. —Journal of the American Medical Association (1900, 1885).
Contesting the Politics of Ethnography: Towards an Alternative Knowledge Production
Authors: Natrajan Balmurli , Parameswaran Radhika
Published: March 2007

We were free, but our bellies were empty. The Master had become the Boss-Medouze, in the film Sugar Cane Alley
Towards the paperless business library: from print to online business information
Authors: Cropley Jacqueline
Published: March 2007

Online information was originally considered as a complement to the existing traditional information resources, but is now replacing them. By rethinking the whole service, cost-effective and time-saving systems have been designed, with the ability to respond to a wide range of enquiries, with greatly reduced overheads. As end-users have been encouraged by the speed and currency of the information, enquiries have increased in number and complexity, although online does not answer everything. Despite having some proficient end-users, the service is still offered from the library as an intermediary. This controls costs and maximises the resources.
Publications produced by major accountancy firms: an undervalued resource
Authors: Rennie Janet , Fielding Linda
Published: March 2007

The publications of seven major accountancy firms were surveyed in 1984/85. These firms are now able to market a whole range of services, and publications should have an important part to play here but, in fact, they are undervalued. The types of publications produced are reports, which are not considered in this account, brochures and technical booklets or guides: the last group is the most useful. The seven firms reviewed produced a total of 742 guides, many of high information content. Most frequent subjects were taxation and overseas business practices but the range was wide. Many are of particular interest to small businesses. Presentation is becoming more modern, but publicity is low and most reviews in the press are of the more traditional guides on, for example, taxation.
Business news coverage in national daily newspapers: a content analysis
Authors: McGrother Carmel
Published: March 2007

Analyses the business content of four leading British national daily newspapers — The Daily Telegraph, The Guardian, The Independent and The Times. Quantifies their coverage of: business; companies; industries/markets; economics; finance; share prices; price comment; other statistical tables; personal finance; management; business policy; business law, industrial relations and business space advertising.
Teaching business information: the Manchester experience
Authors: Kaye David
Published: March 2007

A review of the development of business information courses in the department and an assessment of the present position. Key issues and problems in teaching business information are identified and dis cussed, and prospects for the future are briefly considered.
Finding out about the IT industry
Authors: Hunt Sheila
Published: March 2007

Provides an expert summary of the most useful sources of information on the IT industry. Covers journals, newspapers, directories, abstracts and indexes, online sources, research publications, government publications, publishers, conference proceedings, standards, trade literature, associations and libraries and information services.
All change at Companies House
Authors: Willis Chris
Published: March 2007

Companies House, formerly the Companies Registration Office, keeps detailed financial information on every limited company in the UK. It has recently introduced a host of new services tailored to meet the needs of the business information user.
An Assessment of Methods to Combine Published Survival Curves
Authors: Earle Craig C. , Wells George A.
Published: March 2007

Purpose. To assess the accuracies of different techniques for combining published survival curves, for use in disease modeling applications. Methods. Five methods were identified: 1) iterative generalized least-squares (IGLS), 2) meta-analysis of failure-time data with adjustment for covariates (MFD), 3) nonlinear regression (NLR), 4) log relative risk (LRR), and 5) weighted LRR (w-LRR). Each method was used to combine the survival curves from eight single-arm Phase II trials of chemotherapy in 918 patients with advanced non-small-cell lung cancer (NSCLC). The resulting summary curves were compared with the curve calculated from the corresponding individual patient data (IPD). Results. All methods were able to produce accurate summary survival curves statistically similar to the IPD-derived curve. Maximum discrepancies ranged from 1.8% to 4.7%. MFD appeared to be the most accurate when censoring information was complete. Characteristics of the component trials that adversely affected the accuracies of the different techniques were 1) a high proportion of censored observations (MFD); 2) variability in the length of follow-up (IGLS, NLR, LRR, w-LRR); and 3) the heterogeneity of the treatment results (NLR, w-LRR). Conclusions. All methods were able to accurately reproduce summary survival curves from the published literature. The best method depends on characteristics of the data and the purpose of the analysis. Key words: survival analysis; meta-analysis; life tables; proportional hazards models. (Med Decis Making 2000;20:104-111)
Interpretive Review : Feasibility and Effects of Decision Aids
Authors: Molenaar Sjaak , Sprangers Mirjam A.G. , Postma-Schuit Fenna C.E. , Rutgers Emiel J. Th. , Noorlander Josje , Hendriks Joop , De Haes Hanneke C.J.M.
Published: March 2007

Decision aids for patients have recently been introduced in health care. A literature review was conducted to address the following research questions: 1) which types of decision aids have been developed?; 2) to what extent are they feasible, and acceptable to patients and health care providers?; 3) do decision aids affect the decision-making process and patients' outcomes? Thirty non-controlled (e.g., one-group-only designs) and controlled studies (e.g., randomized experimental designs) were identified. Decision aids were found to be feasible and acceptable to patients and to increase the agreement between patients' values and decisions and patients' knowledge. The effects of decision aids on decisions and on patients' outcomes, including decision uncertainty, satisfaction, and health, have rarely been addressed. When studied, the beneficial effects of decision aids on these outcomes appear to be rather modest. Implications for future development of decision aids and the design of studies are discussed. Key words: shared decision making; patient decision aids. (Med Decis Making 2000;20:112-127)
The Discrete-choice Willingness-to-pay Question Format in Health Economics:
Authors: Smith Richard D.
Published: March 2007

The use of willingness to pay (WTP) in valuing the benefits of health care programs is increasing. Although such values have been denved using open-ended, bidding, or payment-card techniques, recently discrete-choice questionnaires have been advocated, particularly following the report of the National Oceanographic and Atmospheric Administration concerning the validity of using WTP to estimate environmental benefits. It is argued that discrete-choice questions offer a more realistic market, and will therefore lead to more valid responses and yield higher response rates through reduced mental demands. The author reviews these issues in a critical assessment of discrete-choice questions. Key words: Willingness to pay; cost-benefit analysis; health economics; questionnaire format; methodology. (Med Decis Making 2000;20:194-206)
Income Effects of Reduced Health and Health Effects of Reduced Income:
Authors: Sculpher Mark J. , O'Brien Bernie J.
Published: March 2007

There is increasing use of multiattribute health-state utility systems, such as the Health Utilities Index and the EuroQol (now EQ-5D), to estimate quality-adjusted life years (QALYs) for cost-utility analysis. Whereas the preferences elicited from individuals using willingness-to-pay techniques for cost-benefit analysis would be expected to reflect those individuals' income levels, it is often suggested that cost-utility analysis can avoid this income effect by not valuing health in monetary terms. Contrary to this view, the authors argue that income can influence the measurement of utilities used to estimate QALYs. In the context of multiattribute utility instruments, two income effects can take place: 1) when individuals are asked to value health states to generate the set of utilities to apply in subsequent evaluation studies; 2) when those multiattribute systems are used to categonze indimduals' (usually patients') health status in the field in applied evaluation studies. The authors review the most popular utility systems regarding how these income effects are handled and assess the implications for the measurement of utilities using these systems. Key words: cost-utility analyses; health-state valuation; income effects; multiattribute utility instruments. (Med Decis Making 2000;20:207-215)
Withholding Information from Cancer Patients as a Physician's Decision under Risk
Authors: Yaniv Gideon
Published: March 2007

When cancer is diagnosed, the physician may face a dilemma regarding disclosure of information to the patient. While he or she may feel a responsibility to maintain the patient's hope, even through the withholding of information, there is a risk involved: if treatment fails, the patient will eventually know the truth. Patients who would rather live their final days in peace rather than undergo unpleasant treatment of an uncertain nature may be furious and frustrated that they have been deprived of this liberty, ending their lives feeling worse than they would have had they been told the truth at the outset. The author applies three theories of decision making under uncertamty (expected utility theory, prospect theory, and regret theory) to the physician's problem of whether and to what extent to withhold information from a cancer patient, deriving comparative predictions with regard to the relationships between the physician's behavior and illness, patient, and physician characteristics. The results help explain why physicians whose norm of behavior is full disclosure sometimes opt to withhold information and why junior physicians are more likely to disclose the truth than their senior colleagues, as well as the empirical findings that physicians tend to disclose more truthful information to patients the greater the severity of illness and the more inquisitive the patient. Key words: cancer patient; information disclosure/withholding; risk/uncertamty; expected-utility theory; prospect theory; regret theory. (Med Decis Making 2000;20: 216-227)
Population-based Time Preferences for Future Health Outcomes
Authors: Ganiats Theodore G. , Carson Richard T. , Hamm Robert M. , Cantor Scott B. , Sumner Walton , Spann Stephen J. , Hagen Michael D. , Miller Christopher
Published: March 2007

Context. Time preference (how preference for an outcome changes depending on when the outcome occurs) affects clinical decisions, but little is known about determinants of time preferences in clinical settings. Objectives. To determine whether information about mean population time preferences for specific health states can be easily assessed, whether mean time preferences are constant across different diseases, and whether under certain circumstances substantial fractions of the patient population make choices that are consistent with a negative time preference. Design. Self-administered survey. Setting. Family physician waiting rooms in four states. Pa tients. A convenience sample of 169 adults. Intervention. Subjects were presented five clinical vignettes. For each vignette the subject chose between interventions maximizing a present and a future health outcome. The options for individual vignettes varied among the patients so that a distribution of responses was obtained across the population of patients. Main outcome measure. Logistic regression was used to estimate the mean preference for each vignette, which was translated into an implicit discount rate for this group of patients. Results. There were marked differences in time preferences for future health outcomes based on the five vignettes, ranging from a negative to a high positive (116%) discount rate. Conclusions. The study provides empirical evidence that time preferences for future health outcomes may vary substantially among disease conditions. This is likely because the vignettes evoked different rationales for time preferences. Time preference is a critical element in patient decision making and cost-effectiveness research, and more work is necessary to improve our understanding of patient preferences for future health outcomes. Key words: time factors ; models, psychological; attitude to health; outcome assessment (health care). (Med Decis Making 2000;20:263-270)
Willingness to Pay for a Quality-adjusted Life Year
Authors: Hirth Richard A. , Chernew Michael E. , Miller Edward , Fendrick A. Mark , Weissert William G.
Published: March 2007

Cost-benefit analysis (CBA) provides a clear decision rule: undertake an intervention if the monetary value of its benefits exceed its costs. However, due to a reluctance to characterize health benefits in monetary terms, users of cost-utility and cost-effectiveness analyses must rely on arbitrary standards (e.g., < $50,000 per QALY) to deem a program "cost-effective." Moreover, there is no consensus regarding the appropriate dollar value per QALY gained upon which to base resource allocation decisions. To address this, the authors determined the value of a QALY as implied by the value-of-life literature and compared this value with arbitrary thresholds for cost-effectiveness that have come into common use. A literature search identified 42 estimates of the value of life that were appropriate for inclusion. These estimates were classified by method: human capital (HK), contingent valuation (CV), revealed preference/job risk (RP-JR) and revealed preference/non-occupational safety (RP-S), and by U.S. or non-U.S. origin. After converting these value-of-life estimates to 1997 U.S. dollars, the life expectancy of the study population, age-specific QALY weights, and a 3% real discount rate were used to calculate the implied value of a QALY. An ordinary least-squares regression of the value of a QALY on study type and national origin explained 28.4% of the variance across studies. Most of the explained variance was attributable to study type; national origin did not significantly affect the values. Median values by study type were $24,777 (HK estimates), $93,402 (RP-S estimates), $161,305 (CV estimates), and $428,286 (RP-JR estimates). With the exception of HK, these far exceed the "rules of thumb" that are frequently used to determine whether an intervention produces an acceptable increase in health benefits in exchange for incremental expenditures. Key words: cost-effectiveness analysis; cost-utility analysis; quality-adjusted life years; value of life. (Med Decis Making 2000;20:332-342)
A Signal-detection Experiment Measuring the Effect of Computer-aided Detection on Radiologists' Performance
Authors: Ikeda Mitsuru , Ishigaki Takeo , Yamauchi Kazunobu
Published: March 2007

Purpose. To evaluate how the specificity and sensitivity of computer-aided detection (CADe) algorithm outputs affected radiologists' diagnostic performances, the authors studied the effects of 25 simulated CADe algorithms with various sensitivities and specificities (from 60% to 100%). Methods. Six novice radiologists read 200 images that were produced by computer and randomly displayed on CRT, and their detection performances were evaluated with receiver operating characteristic analysis. Results. There were significant differences in performance among CADe types (p < 0.001). Discussion and Conclusion. The overall accuracy of CADe outputs is the most significant factor affecting radiologists' performances in detection and interpretation of images. There is an approximately linear relationship between the sensitivity (specificity) of the CADe output and the reader's sensitivity (specificity), and the slope of reader sensitivity (specificity) as a linear function of CADe sensitivity (specificity) can be considered to be a positive number less than unity. Key words: computers, diagnostic aid; probabilistic judgments; receiver operating characteristic curve (ROC); radiologist decision making; diagnostic concordance. (Med Decis Making 2000;20:343-351)
Early Surgery versus Conservative Management of Dissecting Aneurysms of the Descending Thoracic Aorta
Authors: Katz David , Payne Douglas , Pauker Stephen
Published: March 2007

Background. Optimal management for patients who present acutely with uncomplicated type III dissections of the descending thoracic aorta remains controversial. Patients with dissecting aneurysms represent a subgroup at high risk of rupture who may benefit from early elective surgery as an alternative to standard medical therapy. Methods. The authors constructed a Markov decision model to compare the following clinical strategies: 1) early elective surgery immediately after diagnosis (EARLY SURGERY), 2) medical therapy with periodic computed tomography and with elective surgery when aortic diameter is projected to reach 6 cm (CT FOLLOW-UP), and 3) medical therapy with urgent surgery for dissection-related complications (WATCHFUL WAITING). Data sources included Medline (1966-1995) and a case series of patients with type III dissecting aneurysms who received medical therapy with radiographic follow-up. Results. For a typical 60-year-old patient with an acute, uncomplicated 5-cm dissecting aneurysm of the descending thoracic aorta and an operative 30-day mortality rate of 14% for EARLY SURGERY, the model predicts that EARLY SURGERY improves survival compared with CT FOLLOW-UP (9.91 vs 9.44 QALYs). Conservative management may be preferred for patients who have maximum aneurysm diameters ≤4 cm, are elderly (≥75 years), or have higher-than-expected risk of operative mortality. Conclusions. The choice between early surgery and medical therapy for uncomplicated dissecting aneurysm of the descending thoracic aorta should be tailored to the individual patient's operative risk, risk of dissection-related events, and age. Early surgery may be a reasonable alternative to medical therapy for carefully selected patients at centers with favorable perioperative mortality rates. Key words: thoracic aorta; dissecting aneurysm ; decision support techniques. (Med Decis Making 2000;20:377-393)
A Comparison of HU12 and HU13 Utility Scores in Alzheimer's Disease
Authors: Neumann Peter J. , Sandberg Eileen A. , Araki Sally S. , Kuntz Karen M. , Feeny David , Weinstein Milton C.
Published: March 2007

Purpose. The Health Utilities Index (HUI) is a generic, multiattribute, preference-based health-status classification system. The HUI Mark 3 (HU13) differs from the earlier HUI2 by modifying attributes and allowing more flexibility for capturing high levels of impairment. The authors compared HUI2 and HU13 scores of patients with Alzheimer's disease (AD) and caregivers, and contrasted results of a cost-effectiveness analysis of new drugs for AD using the two systems. Methods. In a cross-sectional study of 679 AD patient/caregiver pairs, stratified by patient's disease stage (questionable/mild/moderate/severe/profound/terminal) and setting (community/assisted living/nursing home), caregivers completed the combined HU12/HU13 questionnaire as proxy respondents for patients and for themselves. Results. Mean (SD) global utility scores for patients were lower on the HU13 (0.22[0.26]) than on the HU12 (0.53 [0.21]). Patient HU13 utility scores ranged from 0.47(0.24) for questionable AD to -0.23 (0.08) for terminal AD, compared with a range of 0.73 (0.15) to 0.14 (0.07) for the HU12. Among the 203 patients in the severe, profound, and terminal stages, 96 (48%) had negative global HU13 utility scores, while none had a negative HU12 score. The utility scores for caregivers were similar on the HUI3 (0.87 [0.14]) and HU12 (0.87 [0.11]). Cost-effectiveness analysis of a new medication to treat AD showed somewhat more favorable results using the HU13. Conclusions. The HU12 and HU13 discriminate well across AD stages. Compared with the HU12, the HUI3 yields lower global utility scores for patients with AD, and more scores for states judged worse than dead. The HUI3 may yield substantially different results from the HU12, particularly for persons who have serious cognitive impairments such as AD. Key words: Health Utility Index; Alzheimer's disease ; utility assessment. (Med Decis Making 2000;20:413-422)
Cardiopulmonary Resuscitation Preferences in Dutch Community-dwelling and Hospitalized Elderly People
Authors: van Mil Annette H.M. , van Klink Rik C.J. , Huntjens Christine , Westendorp Rudi G.J. , Stiggelbout Anne M. , Meinders A.Edo , Lagaay A. Margot
Published: March 2007

Objective. To study the effects of information, gender, quality of life, and hospitalization on cardiopulmonary resuscitation (CPR) preferences and on the wish for information and participation in CPR discussions. Methods. Seventy-five community-dwelling inhabitants of the city of Leiden and 45 consecutive patients in two hospitals in Leiden, The Netherlands, aged 75 years or older, were interviewed about their CPR preferences in their current states of health and in three hypothetical scenarios. Health-related quality of life (QOL) was assessed in separate items. The subjects were asked about their wishes for information and participation in CPR discussions. Results. The chances of surviving CPR were overestimated. After receiving accurate information, 65% of the subjects, more women than men, did not want CPR. Overall QOL did not differ between men and women. Concerning the separate QOL items, men's CPR preferences were more associated with pain, whereas women's were more associated with being impaired in physical functioning and daily and social activities. CPR preferences in the current state of health did not differ significantly between community-dwelling and hospitalized participants. Although only 6% of all participants had ever discussed CPR with their doctors, 70% indicated they wanted routine CPR discussions (either when in good health at home or upon hospital admission), and 61 % preferred to make the final decision about CPR themselves. Conclusions. CPR preferences are affected by different QOL items in men and women. CPR preferences in the current state of health do not differ between hospitalized and community-dwelling elderly people. As the majority of elderly people want CPR discussions, they should be involved in decision making concerning CPR. Key words: cardiopulmonary resuscitation preferences; quality of life; elderly; hospitalization. (Med Decis Making 2000;20:423-429)
Meta-analysis of ROC Curves
Authors: Kester Arnold D.M. , Buntinx Frank
Published: March 2007

The authors present a method to combine several independent studies of the same (continuous or semiquantitative) diagnostic test, where each study reports a complete ROC curve; a plot of the true-positive rate or sensitivity against the false-positive rate or one minus the specificity. The result of the analysis is a pooled ROC curve, with a confidence band, as opposed to earlier proposals that result in a pooled area under the ROC curve. The analysis is based on a two-parameter model for the ROC curve that can be estimated for each individual curve. The parameters are then pooled with a bivariate random-effects meta-analytic method, and a curve can be drawn from the pooled parameters. The authors propose to use a model that specifies a linear relation between the logistic transformations of sensitivity and one minus specificity. Specifically, they define V = In(sensitivity/(1 - sensitivity)) and U = In((1 - specificity)/specificity), and then D = V - U, S = V + U. The model is defined as D = α + β S. The parameters α and β are estimated using weighted linear regression with bootstrapping to get the standard errors, or using maximum likelihood. The authors show how the procedure works with continuous test data and with categorical test data. Key words: diagnostic test; ROC curve; bivariate meta-analysis; bootstrap; maximum likelihood estimate. (Med Decis Making 2000;20:430-439)
Management of Childhood Lead Poisoning
Authors: Glotzer Deborah E. , Freedberg Kenneth A. , Bauchner Howard
Published: March 2007

Objectives. No consensus exists regarding the preferred treatment of childhood lead poi soning. The authors used decision analysis to compare the clinical impacts and cost-ef fectiveness of four management strategies for childhood lead poisoning, and to investigate how effective chelation therapy must be in reducing neuropsychologic sequelae to warrant its use. Methods. The model was based on a 2-year-old child with moderate lead poisoning [blood lead level 1.21 to 1.88 μmol/L (25 to 39 μg/dL)]. The following strategies were compared: 1) no treatment; 2) EDTA provocation testing, followed by chelation if testing is positive (PROV); 3) penicillamine chelation with crossover to EDTA provocation testing if toxicity occurs (PCA); 4) EDTA provocation testing with crossover to penicillamine chelation if testing is negative (EDTA). Results. The EDTA and PCA strategies prevented 22.5% of the cases of reading disability and resulted in an increase of 1.02 quality-adjusted life years compared with no treatment. When the costs of outpatient EDTA testing and chelation are considered, the EDTA strategy is more cost-effective than the PCA strategy; when inpatient costs are considered, the PCA strategy becomes more cost-effective. When costs of remedial education are considered, all strategies are cost-saving compared with no treatment if che lation reduces the risk of lead-induced reading disability by more than 20%. Conclusions. Treatment strategies for childhood lead poisoning vary in clinical impact, cost, and cost- effectiveness. Chelation of the 1.4% of United States preschoolers whose blood lead levels are 1.21 μmol/L (25 μg/dL) or higher could prevent more than 45,000 cases of reading disability, and save more than $900 million per year in overall costs when the costs of remedial education are considered. Key words: lead poisoning; decision analysis; cost anal ysis ; chelation. (Med Decis Making 1995;15:13-24)
The Exclusion of Women from Clinical Trials of Thrombolytic Therapy
Authors: Maynard Charles , Selker Harry P. , Beshansky Joni R. , Griffith John L. , Schmid Christopher H. , Califf Robert M. , D'Agostino Ralph B. , Laks Michael M. , Lee Kerry L. , Wagner Galen S. , Weaver W. Douglas
Published: March 2007

The thrombolytic predictive instrument (TPI) was developed to identify those patients most likely to benefit from thrombolytic therapy for acute myocardial infarction as well as to facilitate the earliest possible administration of this treatment. The TPI consists of predictive models derived from clinical data obtained from both clinical trials and data registries. These models are subject to potential bias due to combinations of primary data from different sources. The purpose of this investigation was to assess the influence of gender in developing the TPI database. In this database, there were 1,096 (22%) women and 3,826 (78%) men; only 38% of the women were enrolled in clinical trials, whereas 46% of the men were (p < 0.0001). Within clinical trials, there were few significant eligibility differences between women and men, as the vast majority of patients met eligibility standards for entry in these trials. However, within clinical registries, the women were older (p < 0.0001) and more often had elevated blood pressure on admission (p = 0.002). Multivariate logistic regression indicated that after adjustment for significant predictors of trial inclusion, women were 25% less likely to be included in clinical trials (odds ratio = 0.76, 95% confidence interval = 0.60, 0.96). In order to counter bias introduced by the exclusion of women from clinical trials, the TPI database included patients from non-trial settings. Carefully including patients from clinical registries or non-trial settings may be an important strategy in constructing generally applicable pre dictive instruments. Key words: thrombolytic predictive instrument; women; gender bias; database. (Med Decis Making 1995;15:38-43)
Comparison of Time-tradeoff Utilities and Rating Scale Values of Cancer Patients and Their Relatives
Authors: O'Leary June F. , Fairclough Diane L. , Jankowski M. Kay , Weeks Jane C.
Published: March 2007

Because they are easy to administer, rating scales are often used as proxies for utility measures. The authors investigated the relationship between time-tradeoff utilities and rating scale values in two populations: 124 cancer patients asked to evaluate their current states of health and 102 relatives and close friends of cancer patients asked to evaluate health- state scenarios. None of the models tested effectively described the relationship between individual patients' rating scale values and time-tradeoff utilities for their current states of health. In contrast, both a plateau and a power-function model explained the variability in the responses of the relatives reasonably well (R2 = 0.56 and R2 = 0.58, respectively). Given that many respondents who were unwilling to trade off any time assigned rating scale values of well below 100, a plateau model may represent the best approach to adjusting rating scale values for health-state scenarios when it is not feasible to elicit time-tradeoff utilities. Key words: time tradeoff; utility; rating scale; cancer; patient preferences; quality of life. (Med Decis Making 1995;15:132-137)
The Person-trade-off Approach to Valuing Health Care Programs
Authors: Nord Erik
Published: March 2007

The person-trade-off technique is a way of estimating the social values of different health care interventions. Basically it consists in asking people how many outcomes of one kind they consider equivalent in social value to X outcomes of another kind. The paper outlines a number of the author's previous studies using the technique. The studies suggest that while the technique is theoretically appealing for resource-allocation purposes, it is in practice quite demanding. It needs to be applied in fairly large groups of subjects to keep random measurement error at an acceptable level. Possible framing effects include the effects of argument presentation and the choice of start points in numerical exercises. To control for these effects, it seems important to take subjects through a multistep procedure, in which they are induced to carefully consider the various arguments that might be relevant in each exercise and to reconsider initial responses in the light of their implications. The investigator must also think through which decision context he or she wishes to study and make his or her choice of context very clear when reporting the results. In spite of these problems, the person-trade-off technique deserves greater attention in the field of cost-utility analysis. Key words: quality-adjusted life years; saved-young-life equivalent (SAVE); person trade-off; equivalence of numbers; health program evaluation. (Med Decis Making 1995;15:201-208)
Assessing Preferences about the DNR Order
Authors: Percy Myra E. , Llewellyn-Thomas Hilary
Published: March 2007

Despite increasing emphasis on advance directives, there has been little methodologic work to assess preferences about the "do not resuscitate" (DNR) order. This developmental work assessed, in a non-patient group, the performance of a probability-trade-off task designed to assess DNR attitudes, in terms of framing effects and stability of preferences. 105 female nursing students each completed one of two versions of the task. In version I ( n = 58), the trade-off moved to increasingly negative descriptions of the outcomes of resuscitation (de creasing chance of survival and increasing risk of brain death), whereas in version II ( n = 47), the trade-off moved to increasingly positive descriptions. One week later, repeat as sessments were obtained for versions I ( n = 35) and II (n = 28). The DNR preference scores were lower and more stable when the task moved to increasingly positive descriptions; perhaps this version of the task tends to weaken risk aversion. These results imply that care should be used in applying a probability trade-off task to the assessment of DNR preferences, since artefactual effects could be induced. Key words : patients' decision making; prefer ences; trade-offs; resuscitation; anchoring effect. (Med Decis Making 1995;15:209-216)
Confidence Intervals for Cost - Effectiveness Ratios
Authors: Gardiner Joseph , Hogan Andrew , Holmes-Rovner Margaret , Rovner David , Griffith Lawrence , Kupersmith Joel
Published: March 2007

The problem of variability in computed cost-effectiveness ratios (CERs) is usually addressed by performing sensitivity analyses to determine the effects on these ratios of plausible ranges of values of input parameters. However, the sampling variation that exists in these estimated parameters can be utilized to obtain confidence intervals for cost-effectiveness ratios. As cost-effectiveness analysis becomes more widely used, new techniques need to be de veloped for establishing when a difference in strategies evaluated is meaningful. A first step is to establish the precision of the CER itself. The authors estimate the precision of a CER in the context of a statistical model in which the primary outcome is survival, with cost and effectiveness defined in terms of the underlying survival distribution (S). Effectiveness (α) is measured by life expectancy, restricted to a finite time horizon and discounted at a fixed rate r, α = √ e-rtS(t)dt. Cumulative cost (β) per patient is regarded as resource utilization and incurred randomly over time depending on the survival experience of the patient, p = √ e - rtS(t)dC(t), where C(t) is the total potential resources utilized up to time t. Average cost effectiveness (ACE) of a single strategy is β/α, and when comparing two strategies, the CER is Δβ/Δα, the ratio of the incremental cost to the difference in mean survival. Utilizing the sampling distribution of the Kaplan-Meier estimate of S yields standard errors and confidence intervals for ACE and CER. The technique is applied to survival data from 218 previously studied patients to assess 95% confidence intervals for the CER and ACE of the implantable cardioverter defibrillator as compared with electrophysiology-guided therapy. Key words: cost-effectiveness analysis; sensitivity analysis; Kaplan-Meier estimate; av erage cost-effectiveness; cardioverter defibrillator; survival data. (Med Decis Making 1995;15:254-263)
Testing an Underlying Assumption on a ROC Curve Based on Rating Data
Authors: Zhou Xiao H.
Published: March 2007

The receiver operating characteristic (ROC) curve is widely accepted as the measurement that best represents the accuracy of a diagnostic system that consists of a diagnostic imaging modality and a reader who is interpreting results from the modality. However, there is one implicit assumption in a ROC curve: that the cutoff points to declare a positive test for decision variables of a diseased patient and a nondiseased patient are the same. If this assumption is violated, then a ROC curve does not exist. The author develops a statistical procedure to test this assumption. To demonstrate, he applies the method to a ROC data set and shows that the assumption of the equal cutoff points could be rejected. Key words: ROC curve; likelihood ratio test; cutoff points. (Med Decis Making 1995;15:276-282)
Continuous Trees and NEVADA Simulation
Authors: Bryg David J.
Published: March 2007

This paper introduces an improved technique for modeling risk and decision problems that have continuous random variables and probabilistic dependence. Variables are modeled with mixtures of four-parameter random variables, called "continuous trees." Functions of random variables are calculated using gaussian quadrature in a manner called "NEVADA simulation" (NumErical integration of Variance And probabilistic Dependence Analyzer). This technique is compared with traditional decision-tree modeling in terms of analytic technique, solution-time complexity, and accuracy. NEVADA simulation takes advantage of the proba bilistic independence in a decision problem while allowing for probabilistic dependence to achieve polynomial computational-time complexity for many decision problems. It improves on the accuracy of traditional decision trees by employing larger approximations than tra ditional decision analysis. It improves on traditional decision analysis by modeling continuous variables with continuous, rather than discrete, distributions. A Bayesian analysis using a mixed discrete-continuous probability distribution for cigarette smoking rate is presented. Key words: continuous trees; NEVADA simulation; decision analysis; modeling. (Med Decis Making 1995;15:318-332)
The Relevance of Searching for Effects under a Clinical-trial Lamppost
Authors: Rittenhouse Brian E.
Published: March 2007

In economic evaluations of new medical technologies, analysts often need to use data from randomized controlled trials. Trials are designed to achieve high internal validity; however, their selected populations and often highly artificial environments may imply low external validity. Thus, the use of trial data in an economic evaluation may bias the results, since economic evaluation is concerned not with theoretical capability in a trial but with likely performance in the practice environment. This paper indicates both the probable bias of one aspect of artificiality in the trial environment—selected populations—and a method of ad justing the analysis so that results will be more likely to reflect actual practice. The judicious use of extra-trial information can be used to correct the biases of clinical trials. Key words: efficacy; effectiveness; clinical trials; diagnosis; external validity; bias; sepsis; bacteremia. (Med Decis Making 1995;15:348-357)
Resampling Techniques in the Analysis of Non-binormal ROC Data
Authors: Mossman Douglas
Published: March 2007

The methods most commonly used for analyzing receiver operating characteristic (ROC) data incorporate "binormal" assumptions about the latent frequency distributions of test results. Although these assumptions have proved robust to a wide variety of actual frequency distributions, some data sets do not "fit" the binormal model. In such cases, resampling techniques such as the jackknife and the bootstrap provide versatile, distribution-indepen dent, and more appropriate methods for hypothesis testing. This article describes the ap plication of resampling techniques to ROC data for which the binormal assumptions are not appropriate, and suggests that the bootstrap may be especially helpful in determining con fidence intervals from small data samples. The widespread availability of ever-faster com puters has made resampling methods increasingly accessible and convenient tools for data analysis. Key words: receiver operating characteristic; ROC; resampling; jackknife; bootstrap; diagnostic testing; diagnostic information; confidence interval. (Med Decis Making 1995;15:358-366)
Valuing the Future
Authors: Chapman Gretchen B. , Elstein Arthur S.
Published: March 2007

Normative discounted utility theory specifies that the values of all future outcomes (for example, those related to health and money) should be discounted at a constant rate. Two experiments demonstrated that, contrary to this prescription, decision makers use different discount rates for health-related decisions and money-related decisions. Temporal discount ings for health and money were similar in that both demonstrated two biases previously found in monetary decisions: discount rates were inversely related to magnitude of outcome and length of delay. The relatively large discount rates used by the subjects suggest why it is often difficult to implement preventive health measures that improve future health. Key words: discounting; intertemporal choice; health decisions. (Med Decis Making 1995;15:373- 386)
Validating Literature-based Models with Direct Clinical Trial Results
Authors: Freedberg Kenneth A. , Hardy W. David , Holzman Robert S. , Tosteson Anna N.A. , Craven Donald E.
Published: March 2007

Objective. To compare literature-based estimates of the cost-effectiveness ratios of strat egies for secondary prophylaxis of Pneumocystis cannit pneumonia (PCP) In AIDS patients with estimates obtained using data from a recent comparative clinical trial Design. A decision- analytic Markov model with data on drug efficacy and toxicity from both the medical literature and a national randomized clinical trial. Drug costs were from average wholesale prices. Discounted life expectancy, total direct medical costs, and cost-effectiveness were projected in dollars per year of life saved (YLS). Setting. Hypothetical for the literature-based model, then the clinical trial results from the multicenter AIDS Clinical Trials Group (ACTG Protocol 021). Patient population. Patients with AIDS and a pnor episode of PCP Interventions. Strategies induded no prophylaxis, TMP-SMX (160/800 mg) daily, or aerosolized pentam idine (300 mg) monthly. Patients experiencing major toxic reactions to either medication would cross over to the other agent. Main results In the literature-based model no prophylaxis was associated with a projected life expectancy of 1.430 years, and total direct cost of $42,080. TMP-SMX increased life expectancy to 2.051 years and cost to $42,300; for aero solized pentamidine life expectancy was 2.066 years and cost $43,960. TMP-SMX had an incremental cost-effectiveness ratio of $350 per YLS compared with no prophylaxis; the incremental ratio for aerosolized pentamidine was $2,950 per YLS when compared with no prophylaxis, but rose to $110,880 per YLS compared with TMP-SMX. When data from ACTG clinical trial 021 were utilized in the model, the incremental cost-effectiveness ratio for TMP- SMX compared with no prophylaxis was $720 per YLS, aerosolized pentamidine was not cost-effective, and was "dominated" by TMP-SMX because it was associated with higher costs and shorter life expectancy. Conclusions. Literature-based cost-effectneness models are useful in developing health policy before clinical trials are completed. Clinical trial results, when available, can be used to validate and revise these models. For secondary PCP prophylaxis in AIDS patients, TMP-SMX is substantially more cost-effective than aerosolized pentamidine. Key words: decision models; cost-effectiveness; Pneumocystis carmu pneu monia. (Med Decis Making 1996;16:29-35)
The Relationship between Cardiac Functional Capacity and Patients' Symptom-specific Utilities for Angina
Authors: Nichol Graham , Llewellyn-Thomas Hilary A. , Thiel Elaine C. , Naylor C. David
Published: March 2007

Forty-one angina patients with coronary disease were interviewed to examine the correlation between prespecified and individualized weights for disease-specific measures of the effects of angina on the patients' well-being. Modifications of the Canadian Cardiovascular Society (CCS) scale for angina and the Duke Activity Specific Index (DASI) were used to rate functional capacity with prespecified items. Disease-specific utilities based on descriptions of functional status were obtained directly, and again indirectly with different anchoring conditions to control for noncardiac comorbidity. Correlations between the functional-capacity measures and the derived utilities were not strong, ranging from -0 25 (p > 0.1) to -0.35 (p = 0.02). Correlation between the two prespecified measures was higher (r = -0.51 or -0.69, both p < 0.01, for DASI versus CCS graded from walking and stair-climbing, re spectively). The direct and indirect disease-specific utility scores were similar (r = 0.92, p < 0.01). The method described provides an approach to measuring disease-specific utilities by adapting existing scales for use in a standard gamble. It confirms that prespecified functional status scores inconsistently reflect patients' valuations of functional states. Further investigation should address whether the observed null effect of comorbidity on disease- specific utilities arose from inadequate coverage of the comorbidity issues in patient inter views or from lack of power given the small size of the feasibility study. Key words: cardiac patients' utilities; cardiac functional capacity; utilities for angina; comorbidity. (Med Decis Making 1996;16:78-85)