Do Not Cross Me Spector, Paul E.
Journal of business and psychology,
04/2019, Letnik:
34, Številka:
2
Journal Article
Recenzirano
The cross-sectional research design, especially when used with self-report surveys, is held in low esteem despite its widespread use. It is generally accepted that the longitudinal design offers ...considerable advantages and should be preferred due to its ability to shed light on causal connections. In this paper, I will argue that the ability of the longitudinal design to reflect causality has been overstated and that it offers limited advantages over the cross-sectional design in most cases in which it is used. The nature of causal inference from a philosophy of science perspective is used to illustrate how cross-sectional designs can provide evidence for relationships among variables and can be used to rule out many potential alternative explanations for those relationships. Strategies for optimizing the use of cross-sectional designs are noted, including the inclusion of control variables to rule out spurious relationships, the addition of alternative sources of data, and the incorporation of experimental methods. Best practice advice is offered for the use of both cross-sectional and longitudinal designs, as well as for authors writing and for reviewers evaluating papers that report results of cross-sectional studies.
Introduction
Durability is a key requirement for the broad acceptance of bariatric surgery. We report on durability at and beyond 10 years with a systematic review and meta-analysis of all reports ...providing data at 10 or more years and a single-centre study of laparoscopic adjustable gastric banding (LAGB) with 20 years of follow-up.
Methods
Systematic review with meta-analysis was performed on all eligble reports containing 10 or more years of follow-up data on weight loss after bariatric surgery. In addition, a prospective cohort study of LAGB patients measuring weight loss and reoperation at up to 20 years is presented.
Results
Systematic review identified 57 datasets of which 33 were eligible for meta-analysis. Weighted means of the percentage of excess weight loss (%EWL) were calculated for all papers included in the systematic review. Eighteen reports of gastric bypass showed a weighted mean of 56.7%EWL, 17 reports of LAGB showed 45.9%EWL, 9 reports of biliopancreatic bypass +/− duodenal switch showed 74.1%EWL and 2 reports of sleeve gastrectomy showed 58.3%EWL. Meta-analyses of eligible studies demonstrated comparable results. Reoperations were common in all groups. At a single centre, 8378 LAGB patients were followed for up to 20 years with an overall follow-up rate of 54%. No surgical deaths occurred. Weight loss at 20 years (
N
= 35) was 30.1 kg, 48.9%EWL and 22.2% total weight loss (%TWL). Reoperation rate was initially high but reduced markedly with improved band and surgical and aftercare techniques.
Conclusion
All current procedures are associated with substantial and durable weight loss. More long-term data are needed for one-anastomosis gastric bypass and sleeve gastrectomy. Reoperation is likely to remain common across all procedures.
Most vertebrates can synthesize vitamin C with synthesis increasing during stress. Humans, however, have lost the ability to synthesize vitamin C. Vitamin C is an important anti-oxidant and an enzyme ...cofactor for many important biological reactions. Sepsis results in the overwhelming production of reactive oxygen species with widespread endothelial, cellular and mitochondrial injury leading to progressive organ failure. Sepsis is associated with an acute deficiency of vitamin C. In experimental sepsis models, intravenous vitamin C reduces organ injury and improves survival. In addition, emerging evidence suggests that the combination of vitamin C, corticosteroids and thiamine may act synergistically to reverse sepsis induced organ dysfunction. These findings are supported by a recent observational study. Randomized controlled trials are underway to investigate this novel approach to the treatment of sepsis.
The Kidney Disease: Improving Global Outcomes (KDIGO) organization developed clinical practice guidelines in 2012 to provide guidance on the evaluation, management, and treatment of chronic kidney ...disease (CKD) in adults and children who are not receiving renal replacement therapy.
The KDIGO CKD Guideline Development Work Group defined the scope of the guideline, gathered evidence, determined topics for systematic review, and graded the quality of evidence that had been summarized by an evidence review team. Searches of the English-language literature were conducted through November 2012. Final modification of the guidelines was informed by the KDIGO Board of Directors and a public review process involving registered stakeholders.
The full guideline included 110 recommendations. This synopsis focuses on 10 key recommendations pertinent to definition, classification, monitoring, and management of CKD in adults.
The 2012 KDIGO Guideline for CKD evaluation, classification, and management has updated the original 2002 KDOQI Guidelines, using newer data and addressing issues raised over the last decade ...concerning definitions and assessment. This review highlights the key aspects of the CKD guideline, and describes the rationale for specific wording and the scope of the document. A précis of key concepts in each of the five sections of the guideline is presented. The guideline document is intended for general practitioners and nephrologists, and covers CKD evaluation, classification, and management for both adults and children. Throughout the guideline, we have attempted to overtly address areas of controversy or non-consensus, international relevance, and impact on practice and public policy.
The natural selection of bad science Smaldino, Paul E.; McElreath, Richard
Royal Society open science,
09/2016, Letnik:
3, Številka:
9
Journal Article
Recenzirano
Odprti dostop
Poor research design and data analysis encourage false-positive findings. Such poor methods persist despite perennial calls for improvement, suggesting that they result from something more than just ...misunderstanding. The persistence of poor methods results partly from incentives that favour them, leading to the natural selection of bad science. This dynamic requires no conscious strategizing—no deliberate cheating nor loafing—by scientists, only that publication is a principal factor for career advancement. Some normative methods of analysis have almost certainly been selected to further publication instead of discovery. In order to improve the culture of science, a shift must be made away from correcting misunderstandings and towards rewarding understanding. We support this argument with empirical evidence and computational modelling. We first present a 60-year meta-analysis of statistical power in the behavioural sciences and show that power has not improved despite repeated demonstrations of the necessity of increasing power. To demonstrate the logical consequences of structural incentives, we then present a dynamic model of scientific communities in which competing laboratories investigate novel or previously published hypotheses using culturally transmitted research methods. As in the real world, successful labs produce more ‘progeny,’ such that their methods are more often copied and their students are more likely to start labs of their own. Selection for high output leads to poorer methods and increasingly high false discovery rates. We additionally show that replication slows but does not stop the process of methodological deterioration. Improving the quality of research requires change at the institutional level.
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