Download or read book Statistical Evaluation of Diagnostic Performance written by Kelly H. Zou and published by CRC Press. This book was released on 2016-04-19 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: Statistical evaluation of diagnostic performance in general and Receiver Operating Characteristic (ROC) analysis in particular are important for assessing the performance of medical tests and statistical classifiers, as well as for evaluating predictive models or algorithms. This book presents innovative approaches in ROC analysis, which are releva

Download or read book Methodology for Evaluation of Diagnostic Performance written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The proliferation of expensive technology in diagnostic medicine demands objective, meaningful assessments of diagnostic performance. Receiver Operating Characteristic (ROC) analysis is now recognized widely as the best approach to the task of measuring and specifying diagnostic accuracy (Metz, 1978; Swets and Pickett, 1982; Beck and Schultz, 1986; Metz, 1986; Hanley, 1989; Zweig and Campbell, 1993), which is defined as the extent to which diagnoses agree with actual states of health or disease (Fryback and Thornbury, 1991; National Council on Radiation Protection and Measurements, 1995). The primary advantage of ROC analysis over alternative methodologies is that it separates differences among diagnostic decisions that are due to actual differences in discrimination capacity from those that are due to decision-threshold effects (e.g., ''under-reading'' or ''over-reading''). An ROC curve measures diagnostic accuracy by displaying True Positive Fraction (TPF: the fraction of patients actually having the disease in question that is diagnosed correctly as ''positive'') as a function of False Positive Fraction (FPF: the fraction of patients actually without the disease that is diagnosed incorrectly as ''positive''). Different points on the ROC curve--i.e., different compromises between the specificity and the sensitivity of a diagnostic test, for a given inherent accuracy--can be achieved by adopting different critical values of the diagnostic test's ''decision variable'' --e.g., the observer's degree of confidence that each case is positive or negative in a diagnostic image-reading task, or the numerical value of the result of a quantitative diagnostic test. ROC techniques have been used to measure and specify the diagnostic performance of medical imaging systems since the early 1970s, and the needs that arise in this application have spurred a variety of new methodological developments. In particular, substantial progress has been made in ROC curve fitting and in developing statistical tests to evaluate the significance of measured differences between ROC curves. These are especially important tasks in medical applications, because various practical issues usually limit the number of patients with clearly established diagnostic truth that can be included in any study that seeks to measure diagnostic performance objectively. Other progress has been made in relating ROC analysis to cost/benefit analysis, and in generalizing ROC methods to accommodate some diagnostic tasks where more than two decision alternatives are available. ROC analysis clearly provides the most rigorous and fruitful approach for such assessments but, like many other powerful techniques that provide useful insight concerning complex situations, it currently suffers from limitations, particularly in evaluation studies that involve small case samples. However, the potential of this relatively new analytic approach and the concepts on which it is based have not been fully explored. The research proposed here is designed to refine and supplement existing ROC methodology to increase both the accuracy and the precision of its results.

Download or read book Improving Diagnosis in Health Care written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2015-12-29 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: Getting the right diagnosis is a key aspect of health care - it provides an explanation of a patient's health problem and informs subsequent health care decisions. The diagnostic process is a complex, collaborative activity that involves clinical reasoning and information gathering to determine a patient's health problem. According to Improving Diagnosis in Health Care, diagnostic errors-inaccurate or delayed diagnoses-persist throughout all settings of care and continue to harm an unacceptable number of patients. It is likely that most people will experience at least one diagnostic error in their lifetime, sometimes with devastating consequences. Diagnostic errors may cause harm to patients by preventing or delaying appropriate treatment, providing unnecessary or harmful treatment, or resulting in psychological or financial repercussions. The committee concluded that improving the diagnostic process is not only possible, but also represents a moral, professional, and public health imperative. Improving Diagnosis in Health Care, a continuation of the landmark Institute of Medicine reports To Err Is Human (2000) and Crossing the Quality Chasm (2001), finds that diagnosis-and, in particular, the occurrence of diagnostic errorsâ€"has been largely unappreciated in efforts to improve the quality and safety of health care. Without a dedicated focus on improving diagnosis, diagnostic errors will likely worsen as the delivery of health care and the diagnostic process continue to increase in complexity. Just as the diagnostic process is a collaborative activity, improving diagnosis will require collaboration and a widespread commitment to change among health care professionals, health care organizations, patients and their families, researchers, and policy makers. The recommendations of Improving Diagnosis in Health Care contribute to the growing momentum for change in this crucial area of health care quality and safety.

Download or read book A Statistical Evaluation Methodology for Measuring the Diagnostic Performance of Medical Expert Systems written by Dorothy Christine Georgakis and published by . This book was released on 1990 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation of diagnostic systems written by John Swets and published by Elsevier. This book was released on 2012-12-02 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Evaluation of Diagnostic Systems: Methods from Signal Detection Theory addresses the many issues that arise in evaluating the performance of a diagnostic system, across the wide range of settings in which such systems are used. These settings include clinical medicine, industrial quality control, environmental monitoring and investigation, machine and metals inspection, military monitoring, information retrieval, and crime investigation. The book is divided into three parts encompassing 11 chapters that emphasize the interpretation of diagnostic visual images by human observers. The first part of the book describes quantitative methods for measuring the accuracy of a system and the statistical techniques for drawing inferences from performance tests. The subsequent part covers study design and includes a detailed description of the form and conduct of an image-interpretation test. The concluding part examines the case study of a medical imaging system that serves as an example of both simple and complex applications. In this part, three mammographic modalities are used: industrial film radiography, low-dose film radiography, and xeroradiography. The case study focuses on the overall reliability of accuracy indices made by its main components, that is, the variabilities across cases, across readers, and within individual readers. The supplementary texts provide study protocols, a computer program for processing test results, and an extensive list of references that will assist the reader in applying those evaluative methods to diagnostic systems in any setting. This book is of value to scientists and engineers, as well as to applied, quantitative, or experimental psychologists who are engaged in the study of the human processes of discrimination and decision making in either perceptual or cognitive tasks.

Download or read book Assessment of Diagnostic Technology in Health Care written by Institute of Medicine and published by National Academies Press. This book was released on 1989-02-01 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Technology assessment can lead to the rapid application of essential diagnostic technologies and prevent the wide diffusion of marginally useful methods. In both of these ways, it can increase quality of care and decrease the cost of health care. This comprehensive monograph carefully explores methods of and barriers to diagnostic technology assessment and describes both the rationale and the guidelines for meaningful evaluation. While proposing a multi-institutional approach, it emphasizes some of the problems involved and defines a mechanism for improving the evaluation and use of medical technology and essential resources needed to enhance patient care.

Download or read book Observer Performance Methods for Diagnostic Imaging written by Dev P. Chakraborty and published by CRC Press. This book was released on 2017-12-14 with total page 591 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gives an accessible overview of R programming for medical imaging and the methods of observer performance testing. Explains the fundamental statistical concepts. Reinforces learning using worked problems and R software code, in addition to examples that utilize standalone ROC software. Starts with basic ROC analysis and builds to extensions of ROC methods for solving more complex but clinically realistic tasks. Emphasizes psychophysical models of observer performance (e.g., binormal model, contaminated binormal model, proper ROC model), and demonstrates how they can give better results than from purely statistical approaches. Supplementary tools and materials available at: www.devchakraborty.com; www.expertcadanalytics.com.

Download or read book Diagnostic Tests Toolkit written by Matthew Thompson and published by John Wiley & Sons. This book was released on 2011-09-29 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diagnostic Tests Toolkit Diagnostic Tests Toolkit Finding the evidence for diagnostic tests Establishing an evidence-based methodology to assess the effectiveness of diagnostic tests has posed problems for many years. Now that the framework is in place health professionals can find and appraise the evidence for themselves. With Diagnostic Tests Toolkit clinicians and junior researchers can interpret the evidence for the effectiveness of different types of diagnostic tests, or develop their own research using the successful ‘step-by-step’ format of the Toolkit series. Written by renowned clinical researchers, this is the first basic guide to evidence-based diagnosis. It is equally valuable to starters in clinical research and those needing a quick refresher on the core elements of evidence-based diagnosis.

Download or read book Diagnostic Measurement written by Andr? A. Rupp and published by Guilford Press. This book was released on 2010-04-09 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive introduction to the theory and practice of diagnostic classification models (DCMs), which are useful for statistically driven diagnostic decision making. DCMs can be employed in a wide range of disciplines, including educational assessment and clinical psychology. For the first time in a single volume, the authors present the key conceptual underpinnings and methodological foundations for applying these models in practice. Specifically, they discuss a unified approach to DCMs, the mathematical structure of DCMs and their relationship to other latent variable models, and the implementation and estimation of DCMs using Mplus. The book's highly accessible language, real-world applications, numerous examples, and clearly annotated equations will encourage professionals and students to explore the utility and statistical properties of DCMs in their own projects. This book will appeal to professionals in the testing industry; professors and students in educational, school, clinical, and cognitive psychology. It will also serve as a useful text in doctoral-level courses in diagnostic testing, cognitive diagnostic assessment, test validity, diagnostic assessment, advanced educational measurement, psychometrics, and item response theory

Download or read book Handbook of Diagnostic Classification Models written by Matthias von Davier and published by Springer Nature. This book was released on 2019-10-11 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook provides an overview of major developments around diagnostic classification models (DCMs) with regard to modeling, estimation, model checking, scoring, and applications. It brings together not only the current state of the art, but also the theoretical background and models developed for diagnostic classification. The handbook also offers applications and special topics and practical guidelines how to plan and conduct research studies with the help of DCMs. Commonly used models in educational measurement and psychometrics typically assume a single latent trait or at best a small number of latent variables that are aimed at describing individual differences in observed behavior. While this allows simple rankings of test takers along one or a few dimensions, it does not provide a detailed picture of strengths and weaknesses when assessing complex cognitive skills. DCMs, on the other hand, allow the evaluation of test taker performance relative to a potentially large number of skill domains. Most diagnostic models provide a binary mastery/non-mastery classification for each of the assumed test taker attributes representing these skill domains. Attribute profiles can be used for formative decisions as well as for summative purposes, for example in a multiple cut-off procedure that requires mastery on at least a certain subset of skills. The number of DCMs discussed in the literature and applied to a variety of assessment data has been increasing over the past decades, and their appeal to researchers and practitioners alike continues to grow. These models have been used in English language assessment, international large scale assessments, and for feedback for practice exams in preparation of college admission testing, just to name a few. Nowadays, technology-based assessments provide increasingly rich data on a multitude of skills and allow collection of data with respect to multiple types of behaviors. Diagnostic models can be understood as an ideal match for these types of data collections to provide more in-depth information about test taker skills and behavioral tendencies.

Download or read book Principles and Practice of Clinical Trials written by Steven Piantadosi and published by Springer Nature. This book was released on 2022-07-19 with total page 2573 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a comprehensive major reference work for our SpringerReference program covering clinical trials. Although the core of the Work will focus on the design, analysis, and interpretation of scientific data from clinical trials, a broad spectrum of clinical trial application areas will be covered in detail. This is an important time to develop such a Work, as drug safety and efficacy emphasizes the Clinical Trials process. Because of an immense and growing international disease burden, pharmaceutical and biotechnology companies continue to develop new drugs. Clinical trials have also become extremely globalized in the past 15 years, with over 225,000 international trials ongoing at this point in time. Principles in Practice of Clinical Trials is truly an interdisciplinary that will be divided into the following areas: 1) Clinical Trials Basic Perspectives 2) Regulation and Oversight 3) Basic Trial Designs 4) Advanced Trial Designs 5) Analysis 6) Trial Publication 7) Topics Related Specific Populations and Legal Aspects of Clinical Trials The Work is designed to be comprised of 175 chapters and approximately 2500 pages. The Work will be oriented like many of our SpringerReference Handbooks, presenting detailed and comprehensive expository chapters on broad subjects. The Editors are major figures in the field of clinical trials, and both have written textbooks on the topic. There will also be a slate of 7-8 renowned associate editors that will edit individual sections of the Reference.

Download or read book Statistical Methods in Diagnostic Medicine written by Xiao-Hua Zhou and published by John Wiley & Sons. This book was released on 2014-08-21 with total page 597 pages. Available in PDF, EPUB and Kindle. Book excerpt: Praise for the First Edition " . . . the book is a valuable addition to the literature in the field, serving as a much-needed guide for both clinicians and advanced students."—Zentralblatt MATH A new edition of the cutting-edge guide to diagnostic tests in medical research In recent years, a considerable amount of research has focused on evolving methods for designing and analyzing diagnostic accuracy studies. Statistical Methods in Diagnostic Medicine, Second Edition continues to provide a comprehensive approach to the topic, guiding readers through the necessary practices for understanding these studies and generalizing the results to patient populations. Following a basic introduction to measuring test accuracy and study design, the authors successfully define various measures of diagnostic accuracy, describe strategies for designing diagnostic accuracy studies, and present key statistical methods for estimating and comparing test accuracy. Topics new to the Second Edition include: Methods for tests designed to detect and locate lesions Recommendations for covariate-adjustment Methods for estimating and comparing predictive values and sample size calculations Correcting techniques for verification and imperfect standard biases Sample size calculation for multiple reader studies when pilot data are available Updated meta-analysis methods, now incorporating random effects Three case studies thoroughly showcase some of the questions and statistical issues that arise in diagnostic medicine, with all associated data provided in detailed appendices. A related web site features Fortran, SAS®, and R software packages so that readers can conduct their own analyses. Statistical Methods in Diagnostic Medicine, Second Edition is an excellent supplement for biostatistics courses at the graduate level. It also serves as a valuable reference for clinicians and researchers working in the fields of medicine, epidemiology, and biostatistics.

Download or read book Advances in Patient Safety written by Kerm Henriksen and published by . This book was released on 2005 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: v. 1. Research findings -- v. 2. Concepts and methodology -- v. 3. Implementation issues -- v. 4. Programs, tools and products.

Download or read book Cognitive Diagnostic Assessment for Education written by Jacqueline Leighton and published by Cambridge University Press. This book was released on 2007-05-14 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the current push toward educational reform, there is great potential for innovation and change, particularly in large scale testing. One area where change is possible is in cognitive diagnostic assessment. Researchers in educational measurement and cognitive psychology are finally in a position to design tests targeted specifically for providing valuable information about students' cognitive strengths and weaknesses. This self-contained volume organizes what is known about cognitive diagnostic assessment in education, including its conceptual and philosophical basis, methods, and applications. The complete list of topics includes educational demand, philosophical rationale, construct validity, cognitive methods, test construction, statistical models, and unresolved issues (e.g., how to best translate diagnostic information into teaching practices). Leighton and Gierl present a comprehensive and up-to-date examination of cognitive diagnostic assessment in education.

Download or read book The Evidence Base of Clinical Diagnosis written by J. Andre Knottnerus and published by BMJ Books. This book was released on 2009-01-26 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique book presents a framework for the strategy and methodology of diagnostic research, in relation to its relevance for practice. Now in its second edition The Evidence Base of Clinical Diagnosis has been fully revised and extended with new chapters covering the STARD guidelines (STAndards for the Reporting of Diagnostic accuracy studies) and the multivariable analysis of diagnostic data. With contributions from leading international experts in evidence-based medicine, this book is an indispensable guide on how to conduct and interpret studies in clinical diagnosis. It will serve as a valuable resource for all investigators who want to embark on diagnostic research and for clinicians, practitioners and students who want to learn more about its principles and the relevant methodological options available.

Download or read book Prosthetic Joint Infections written by Trisha Peel and published by Springer. This book was released on 2017-11-28 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book outlines the most updated clinical guidelines that are vital for the prevention infections and care of patients with joint infections following a replacement surgery, one of the highest volume medical interventions globally. Sections address the diagnosis, management approaches and prevention of prosthetic joint infections. Written by experts in the field, this text provides a brief overview of the literature and current recommendations in each of the specified areas. Given the rapidly evolving state-of-play in this clinical area, this compendium grows increasingly important to clinicians in their management decisions. Prosthetic Joint Infections is a valuable resource for infectious disease specialists, epidemiologists, surgeons, and orthopedic specialists who may work with patients with prosthetic joint infections.

Download or read book Statistical Methods for Combining Diagnostic Tests and Performance Evaluation Metrics written by Chengning Zhang (Ph.D.) and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In biomedical studies, it is usually the case that several diagnostic tests can be performedon an individual or multiple disease markers are available simultaneously, and that many of them may be associated with the clinical outcome. In practice, a single test or marker often has limited diagnostic performance. Therefore, it is important to combine multiple sources of information available to achieve higher classification performance. This dissertation focuses on statistical methods for combining multiple diagnostic tests and the corresponding performance evaluation metrics. In the first project, we provide a survey of the current state of the art in methods for combining multiple tests. We categorize existing methods into three general groups and conduct extensive simulation studies to compare the performance of different combination methods. The reviewed methods serve as benchmark for developing new combination approaches in the following projects. In the second project, we consider the problem of combining multiple tests whose values are missing at random (MAR). In addition, we aim to exploit the known monotonicity relationship between the input variables and the disease outcome for gains in diagnostic accuracy. We develop a novel likelihood-based approach to monotone classification that accounts for missing inputs in a natural and principled way. The risk score function is obtained through the nonparametric maximum likelihood estimation (NPMLE). A novel expectation-maximization (EM)-type algorithm is devised to compute the NPMLE by treating the monotonicity-constrained risk score function as a cumulative distribution for a latent random vector. Through simulation studies and a real data example, we demonstrate that the proposed method outperforms state-of-the-art methods for combining multiple inputs under monotonic assumption, especially when the inputs contain missing data. We illustrate our approach with a dataset from a recent nonalcoholic fatty liver disease (NALFD) study. In the third project, our approach established in the second part is extended to the scenario where one covariate is randomly censored. The proposed approach consists of two steps. In step one, we use a Cox proportional hazards model for the distribution of the censored covariate given other covariates in the model, this conditional distribution is used for calculating the observed likelihood of data. In step two, a similar expectation maximization (EM)-type algorithm is devised, based on observed data likelihood from step one, to compute the NPMLE of the monotonicity-constrained risk score function. Through simulation studies, we demonstrate that the proposed method outperforms the simple but inefficient complete-case analysis as well as the substitution methods. We apply our method to the data set from a primary biliary cirrhosis (PBC) study conducted at Mayo Clinic. The proposed methods in part two and three can be extended to multi-class cases, where the labels have an inherent order but no meaningful numeric distance between them. A natural question arises as to how to evaluate the classification performance under such setting. Therefore, in the fourth project, we consider the problem of performance evaluation metrics for ordinal classification. We propose three novel performance evaluation metrics that better capture the ordinality of the outcomes. The first metric is adapted from the area under the receiver operating characteristic (ROC) curve (AUC), while the latter two are simple and interpretable generalizations of the Harrell's concordance index (C-INDEX). Moreover, we show the optimality of the AUC based metrics through Neyman-Pearson lemma. We conduct extensive simulation studies to confirm the usefulness of the proposed performance metrics for ordinal classification.