2,497 publications from this institution
In most systematic reviews containing meta-analyses of evidence for health care interventions, very recent studies are rare. Researchers who conduct systematic reviews with meta-analyses, and clinicians who read the outcomes of these studies, should be made aware of the potential implications of including less recent data.
<p>PDF - 418KB, Global distribution of EGRP-supported cancer epidemiology consortia (CEC)-affiliated teams.</p>
Data continue to accumulate indicating that many systematic reviews are methodologically flawed, biased, redundant, or uninformative. Some improvements have occurred in recent years based on empirical methods research and standardization of appraisal tools; however, many authors do not routinely or consistently apply these updated methods. In addition, guideline developers, peer reviewers, and journal editors often disregard current methodological standards. Although extensively acknowledged and explored in the methodological literature, most clinicians seem unaware of these issues and may automatically accept evidence syntheses (and clinical practice guidelines based on their conclusions) as trustworthy. A plethora of methods and tools are recommended for the development and evaluation of evidence syntheses. It is important to understand what these are intended to do (and cannot do) and how they can be utilized. Our objective is to distill this sprawling information into a format that is understandable and readily accessible to authors, peer reviewers, and editors. In doing so, we aim to promote appreciation and understanding of the demanding science of evidence synthesis among stakeholders. We focus on well-documented deficiencies in key components of evidence syntheses to elucidate the rationale for current standards. The constructs underlying the tools developed to assess reporting, risk of bias, and methodological quality of evidence syntheses are distinguished from those involved in determining overall certainty of a body of evidence. Another important distinction is made between those tools used by authors to develop their syntheses as opposed to those used to ultimately judge their work. Exemplar methods and research practices are described, complemented by novel pragmatic strategies to improve evidence syntheses. The latter include preferred terminology and a scheme to characterize types of research evidence. We organize best practice resources in a Concise Guide that can be widely adopted and adapted for routine implementation by authors and journals. Appropriate, informed use of these is encouraged, but we caution against their superficial application and emphasize their endorsement does not substitute for in-depth methodological training. By highlighting best practices with their rationale, we hope this guidance will inspire further evolution of methods and tools that can advance the field.
Among cancer prognostic marker studies, reporting quality of design and assay information often appears suboptimal, indicating that this literature may be largely unreliable. Given the potential clinical importance of prognostic marker information, improved design and reporting of these studies are warranted.
Attacks against Internet routing are increasing in number and severity. Contributing greatly to these attacks is the absence of origin authentication; there is no way to validate claims of address ownership or location. The lack of such services not only enables attacks by malicious entities, but also indirectly allows seemingly inconsequential misconfigurations to disrupt large portions of the Internet. This paper considers the semantics, design, and costs of origin authentication in interdomain routing. We formalize the semantics of address delegation and use on the Internet, and develop and characterize original, broad classes of origin authentication proof systems. We estimate the address delegation graph representing the current use of IPv4 address space using available routing data. This effort reveals that current address delegation is dense and relatively static: as few as 16 entities perform 80 % of the delegation on the Internet. We conclude by evaluating the proposed services via trace-based simulation, which demonstrates that the enhanced proof systems can significantly reduce resource costs associated with origin authentication.
This paper describes an extractor designed to produce resistance values for use in digital circuit simulation. REDS avoids resistance extraction on most nets in a design using a simple filter based on the perimeter and area values calculated by the capacitance extractor, allowing it to concentrate on areas where resistance may substantially affect circuit timing. Nets are extracted using a fast square counting algorithm, and simplified before output to remove spurious elements. REDS is designed to work on the Magic layout database.
This Viewpoint examines the increase in “mega-journals” (prolific publishers of medical articles) and both the opportunities and threats to scientific research they present.
Guideline recommendations and health policy decisions rely on evidence from clinical and epidemiological studies. Adequate methodology and appropriate conclusions are essential to support healthcare and health policy decisions. An analysis of body mass index and mortality by the Global BMI Mortality Collaboration (GBMC) concluded that the association of excess body weight with higher mortality was similar worldwide and that overweight and obesity should be combated everywhere. To reach this conclusion, the GBMC used highly selected data, rather than a systematic approach. The GBMC initially chose individual participant data from 239 prospective studies with approximately 10.6 million participants. The GBMC then excluded over 60% of data and over 75% of fatal events by eliminating all cases with any reported disease at baseline or smoking history and all events within the first 5 years of follow‐up. After applying these restrictions, the association of overweight with lower mortality was reversed and the association of obesity with higher mortality was increased. Given the major flaws in the selection process, in the adequacy of the data, in the data analysis, and in the interpretation, the GBMC conclusions should be viewed sceptically as a guide to action, either for clinical decisions or for public health in general. The flawed conclusion that overweight is uniformly associated with substantially increased risk of death and thus should be combated in any circumstances may lead not only to unjustified treatment efforts and potential harm in a wide range of clinical conditions but also to a tremendous waste of resources.
