1,720,977 research outputs found
Why are clinicians reluctant to treat smear-negative tuberculosis? An inquiry about treatment thresholds in Rwanda
No full textPURPOSE: The diagnosis of tuberculosis remains controversial between clinicians and public health officers. Public health officials fear to treat too many patients; clinicians fear that truly diseased will be denied treatment. We wondered whether an analysis of the treatment threshold could help making the often intuitive decision to treat smear-negative cases more evidence based. METHODS: Eighteen clinicians and 10 public health specialists were asked for an intuitive estimate of their treatment threshold for tuberculosis and of key determinant factors for this threshold: the magnitude and subjective weight of mortality and morbidity due to both the disease and the treatment and risk and cost of the latter. With these factors, the authors calculated treatment thresholds and compared them to the intuitive thresholds of the interviewees. A prescriptive threshold was calculated based on literature data, omitting cost and subjective factors. RESULTS: The median overall intuitive treatment threshold was 52.5%, the calculated 11.9%, and the prescriptive 2.7%. For 2 factors, public health officers provided significantly lower values than clinicians: cost of treatment (median = 20 dollars v. 300 dollars; U = 2.5; P = 0.0002); cost of life (median = 500 dollars v. 5000 dollars; U = 17.5; P = 0.009). CONCLUSION: These results suggest that clinicians and public health officers estimate wrongly the threshold even when using their own subjective estimate of influencing factors. Omitting treatment cost and subjective weight of provoked harm can result in a very low threshold. Sound training in threshold principles and providing tools to correctly assess data might help in making better decisions in tuberculosis in developing countries
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Effect of applying a treatment threshold in a population. An example of pulmonary tuberculosis in Rwanda
No full textPurpose Clinicians often think treatment thresholds should be adapted to the setting. We intended to explore the effect in terms of harm because of false negatives and true and false positives of the application of a treatment threshold for pulmonary tuberculosis from a patient's perspective at different prevalence levels in a developing country. Methods In a cohort of 300 patients with chronic cough, we estimated the prevalence of pulmonary tuberculosis, and the sensitivity and specificity of key predictors with latent class analysis (LCA). We computed the post-test probability of individual patients based on these data. With disease- and treatment-related mortality and morbidity, and without cost or regret, we calculated the break-even point of disease probability where treating versus not treating resulted in similar total harm from the patient's perspective. We estimated the total harm of applying this threshold to the cohort, and to hypothetical settings with different disease prevalence. Results The threshold was computed at 0.026, suggesting treatment for all patients of the cohort. Hypothetically lowering the prevalence showed that the lowest total harm in the cohort always coincides with this threshold, but that numbers of treated patients drop considerably. Conclusion For pulmonary tuberculosis a decision threshold solely based on utilities without cost or regret leads to a very low threshold. The lowest total harm is found always at this disease probability, irrespective of the distribution of the patients. Although these findings might suggest an excess prescription at reference level, this is not the case in settings with lower prevalenc
Weighing harm in therapeutic decisions of smear-negative pulmonary tuberculosis
No full textPURPOSE: To relate the intuitive weight of harm by commission and harm by omission in therapeutic decisions for pulmonary tuberculosis, and to compare it with a weight based on probabilities. METHODS: Clinicians were asked for an estimation of probabilities related with the outcome of treated and nontreated pulmonary tuberculosis and for the toll of wrong decisions. Three ratios of the weight of forgoing a treatment in false-negative patients against the weight of treating false-positives were calculated. The first was based on intuitive estimations, whereas the second and third were based on calculated, either through intuitive estimations of probabilities or through literature data. The association between experience and the difference between the intuitive and the calculated ratios was assessed. RESULTS: Eighty-one participants from Ecuador, Laos, Nepal, and Rwanda responded. The ratio of intuitive weights was 2.0 (interquartile range [IQR], 1.0-4.0) and the ratio of calculated weights based on intuitive probabilities was 64 (IQR, 25.0-169.6; P < 0.001). The ratio of calculated weight based on literature probabilities was 30 (IQR, 17.9-59.2). No association (R(2) = 0.03) was found between experience and accuracy in estimating the weight of errors. CONCLUSION: The weight of a false negative is more important than the weight of a false positive for therapeutic decisions in pulmonary tuberculosis. The ratio of the intuitively estimated weights was much lower than the calculation based on intuitively estimated influencing factors. Clinicians were accurate in estimating probabilities but failed to incorporate them into therapeutic decisions
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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