1,721,029 research outputs found
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
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
Assessing the impact of missing data on hospital performance profiling
No full textIschemic stroke is a leading cause of mortality, long-term disability, and high healthcare costs in the US. In light of this clinical and financial burden, the Centers for Medicare & Medicaid Services (CMS) has decided to incorporate ischemic stroke measures of 30-day mortality and hospital readmission into its current pay-for-performance program. This decision has come under intense scrutiny, as many clinicians and researchers believe that the current risk adjustment model is inadequate because it does not include a measure of stroke severity. Due to its well-documented importance in individual-level prediction, there is concern that excluding a measure of stroke severity from risk adjustment will lead to incorrect rankings of hospital performance, i.e. hospital profiling. However, administrative datasets used in CMS currently do not capture a measure of stroke severity, such as the National Institutes of Health Stroke Scale (NIHSS), and in clinical databases which capture NIHSS, it is frequently missing. Little work has been done to asses if the documentation of NIHSS is biased, and if so, what impact bias would have on hospital-level estimates of mortality. In this study, we analyzed data from ischemic stroke patients from an existing stroke registry to identify patterns and characteristics that predict NIHSS documentation at the patient- and hospital-level. Next, we tested for the presence of selection bias in patients with documented NIHSS using the Heckman Selection Model. Finally, using computer simulations, we estimated the impact of missing NIHSS data on hospital profiling of 30-day mortality, under different assumptions about the prevalence and mechanism of missing NIHSS data. We found that patients with documented NIHSS were, in fact, a biased subsample of all ischemic stroke patients. Documentation of NIHSS was driven by a combination of patient-level and hospital-level factors. At the patient- and hospital-level, analyses suggested that patients with more severe strokes (i.e. increased NIHSS score) were better documented than patients with less severe strokes. These findings were confirmed using the Heckman Selection Model. However, in both analyses, we found that the amount of bias was modest. In computer simulations, we quantified the impact that missing data would have on the accuracy of hospital ischemic stroke profiling, under different assumptions about how NIHSS data was missing. Any effect of missing NIHSS mechanism was trumped by the impact of missingness on sample size. Because patients with missing NIHSS data were dropped from risk-adjustment models as documentation of NIHSS decreased, the accuracy of hospital risk-standardized mortality rates (RSMRs) estimated by the hierarchical logistic model deteriorated. All of our findings were substantially modified by the hospital ischemic stroke volume, with low volume hospital suffering the worst accuracy. These results are a reflection of the fact that the loss of sample size (either through the documentation rate or hospital volume), increases the amount of shrinkage in RSMR estimates, which makes any random noise more impactful on changes in RSMR. Overall, our findings raise concerns about the addition of NIHSS data into risk adjustment models for hospital-level ischemic stroke outcomes, and illustrate shortcomings in current methodologies used to profile hospitals. It is crucial that data used in risk adjustment for hospital profiling be documented with very high levels of completeness.Thesis (Ph. D.)--Michigan State University. Epidemiology, 2015Includes bibliographical references (pages 115-127
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Essays on the economics of organ transplantation and hemodialysis
No full textChapter 1. The Effect of Broader Liver Sharing on Patient Outcomes and Offer Acceptance: This paper evaluates a liver allocation policy known as Share 35, which provides transplant candidates facing high mortality risks with priority for livers obtained from relatively distant geographic areas. Exploiting the variation in the access to liver transplants across transplant candidates, I show that increasing access to liver transplants is an effective way to reduce mortality rates. Although the policy is well-targeted, I find that the policy causes unintended effects on the quality of transplanted livers and transplant candidates' liver offer-acceptance incentives. Because the policy promotes liver sharing across areas, targeted candidates receive a lower quality of livers due to longer liver transportation times. However, those candidates receive a compensation on liver quality by receiving livers with better donor characteristics. To further understand the mechanism of the compensation, I develop a strategic liver search model and estimate the model with match-run data that contain offer-acceptance decision histories for all donated livers. I find that the policy enables targeted candidates to be more selective of liver and transfer some of their quality loss to others.Chapter 2. The Role of Kidney Allocation Policy in Addressing Kidney Shortages: I examine whether prioritizing certain types of transplant candidates in deceased-donor kidney allocation can increase the total number of kidney transplants. Transplant candidates strategically choose one of the two kidney sources, namely, deceased-donor and living-donor kidneys. While deceased-donor kidneys are available for all transplant candidates (similar to public goods), living-donor kidneys are only available for the designated recipients by the donors (similar to private goods). Using a regression discontinuity design, I show that transplant candidates are less likely to choose living-donor kidneys when they have better access to deceased-donor kidneys, which can be interpreted as a crowd-out effect. Furthermore, I find that the size of the effect varies substantially across race, blood type, and dialysis status of transplant candidates. The result implies that prioritizing transplant candidates, who are less prone to crowd-out, in deceased-donor kidney allocation could make policies designed to increase the number of deceased donors more effective.Chapter 3. The Strategic Location Choice of For-profit Hemodialysis Facilities in the U.S.: In the last chapter, I identify key factors related to the location choice of for-profit hemodialysis facilities using a dataset from the United States Renal Data System (USRDS) and structural methods. All patients with kidney failure need to receive hemodialysis treatment regularly and permanently. Because dialysis treatments are homogeneous across facilities, patients are likely to choose a treatment facility based on the distance from their homes. The strategic model introduced by Seim (2006) involves a static and incomplete information game among dialysis facilities for entry and positioning in a market. The estimation results show that in choosing an optimal location, a tradeoff occurs between local demand and competition with potential entrants.Thesis (Ph. D.)--Michigan State University. Economics, 2020Includes bibliographical reference
ANALYZING THE QUALITY OF PREHOSPITAL STROKE CARE IN MICHIGAN : LEVERAGING A STATE-WIDE STROKE REGISTRY TO QUANTIFY VARIATION IN EMS CARE AND IDENTIFY PREHOSPITAL PERFORMANCE METRICS ASSOCIATED WITH OPTIMAL DOWNSTREAM CARE
Get PDFIntroduction: Acute stroke is a debilitating condition responsible for substantial morbidity and mortality and for which the efficacy of treatment is highly time dependent. As such, emergency medical services (EMS) are a key link in the stroke \u201cchain of recovery.\u201d However, studies of EMS stroke care are limited and suggest a high degree of variability in care. Methods: This analysis utilized linked data from state-level EMS and stroke registries in Michigan to perform an audit of EMS compliance with 6 performance measures derived from clinical guidelines, determine factors contributing to variability in compliance, and examine associations between EMS performance and downstream stroke care.Results: Among 5708 EMS-transported stroke cases identified between January 2018 and July 2019, compliance with performance measures varied widely. Patients with subarachnoid hemorrhage, those with very low or high stroke severity, and those who presented later tended to receive less compliant EMS care and there was substantial group-level variability between EMS agencies. In multivariable models, compliance with each of the EMS performance measures was associated with early CT acquisition in the Emergency Department. EMS stroke recognition and hospital prenotification were also associated with the odds of receiving timely acute ischemic stroke treatment with alteplase.Conclusions: EMS compliance with recommended practices for stroke was variable in Michigan and is influenced by both patient-level and EMS agency-level factors. EMS compliance with performance measures also predicts favorable stroke care following hospital arrival.Thesis (M.S.)--Michigan State University. Epidemiology - Master of Science, 2021Includes bibliographical reference
- …
