19 papers · ranked by Valyu relevance
Zhongheng Zhang, Xiao Xu, Hongying Ni
Introduction Small-study effects refer to the fact that trials with limited sample sizes are more likely to report larger beneficial effects than large trials. However, this has never been investigated in critical care medicine. Thus, the present study aimed to examine the presence and extent of small-study effects in…
Lucy Lu, Qi Sheng Phua, Stephen Bacchi, Rudy Goh + 4 more
Small study effects are the phenomena in which smaller studies have a tendency to show greater effect sizes than larger studies.1 Potential causes of small study effects are largely categorized into bias, heterogeneity, and pure coincidence.2 A well-known explanation for small study effects is publication bias,3,4 in…
Yun Hyung Koog, Seo Ryang We, Byung-Il Min, Ulrich Thiem
Background It has been argued that placebos may not have important clinical impacts in general. However, there is increasing evidence of a publication bias among trials published in journals. Therefore, we explored the potential for publication bias in randomized trials with active treatment, placebo, and no-treatment…
Chuan Hong, Georgia Salanti, Sally C. Morton, Richard D. Riley + 3 more
'Haitao Chu' 'Stephen E. Kimmel' 'Yong Chen'] Summary: Small study effects occur when smaller studies show different, often larger, treatment effects than large ones, which may threaten the validity of systematic reviews and meta-analyses. The most well-known reasons for small study effects include publication bias…
Fernando Pires Hartwig, George Davey Smith, Amand Floriaan Schmidt, Jack Bowden
Meta-analyses based on systematic literature reviews are commonly used to obtain a quantitative summary of the available evidence on a given topic. Despite its attractive simplicity, and its established position at the summit of the evidence-based medicine hierarchy, the reliability of any meta-analysis is largely…
Lisa Holper
Background Recent meta-analyses reported placebo response rate in antidepressant trials to be stable since the 1970s. These meta-analyses however were limited in considering only linear time trends, assessed trial-level covariates based on single-model hypothesis testing only, and did not adjust for small-study effects…
Anthony Steven Dick, Ashley L. Watts, Steven Heeringa, Daniel A. Lopez + 18 more
The Adolescent Brain Cognitive Development (ABCD) Study is the largest single-cohort prospective longitudinal study of neurodevelopment and children’s health in the United States. A cohort of n= 11,880 children aged 9-10 years (and their parents/guardians) were recruited across 22 sites and are being followed with…
Jack Bowden, Christopher Jackson
Summary. The funnel plot is a graphical visualisation of summary data estimates from a meta-analysis, and is a useful tool for detecting departures from the standard modelling assumptions. Although perhaps not widely appreciated, a simple extension of the funnel plot can help to facilitate an intuitive interpretation…
Maximilian A. Primbs, Charlotte R. Pennington, Daniël Lakens, Miguel Alejandro A. Silan + 4 more
Psychological Science? A Reply to Götz et al. (2022) Authors: ['Maximilian A. Primbs' 'Charlotte R. Pennington' 'Daniël Lakens' 'Miguel Alejandro A. Silan' 'Dwayne S. N. Lieck' 'Patrick S. Forscher' 'Erin M. Buchanan' 'Samuel J. Westwood'] In the January 2022 issue of Perspectives, Götz et al. argued that small effects…
Shinichi Nakagawa, Malgorzata Lagisz, Yefeng Yang, Szymon M. Drobniak
'Szymon M. Drobniak'] Power analysis currently dominates sample size determination for experiments, particularly in grant and ethics applications. Yet, this focus could paradoxically result in suboptimal study design because publication biases towards studies with the largest effects can lead to the overestimation of…
Herm J. Lamberink, Willem M. Otte, Michel R.T. Sinke, Daniël Lakens + 3 more
Biomedical studies with low statistical power are a major concern in the scientific community and are one of the underlying reasons for the reproducibility crisis in science. If randomized clinical trials, which are considered the backbone of evidence-based medicine, also suffer from low power, this could affect…
Enxuan Lin, Tiejun Tong, Yong Chen, Yuedong Wang
few studies Authors: ['Enxuan Lin' 'Tiejun Tong' 'Yong Chen' 'Yuedong Wang'] According to Davey et al. (2011) with a total of 22,453 meta-analyses from the January 2008 Issue of the Cochrane Database of Systematic Reviews, the median number of studies included in each meta-analysis is only three. In other words, about…
Tim Friede, Christian Röver, Simon Wandel, Beat Neuenschwander
Meta-analyses in orphan diseases and small populations generally face particular problems including small numbers of studies, small study sizes, and heterogeneity of results. However, the heterogeneity is difficult to estimate if only very few studies are included. Motivated by a systematic review in immunosuppression…
Clarissa F. D. Carneiro, Thiago C. Moulin, Malcolm R. Macleod, Olavo B. Amaral
Proposals to increase research reproducibility frequently call for focusing on effect sizes instead of p values, as well as for increasing the statistical power of experiments. However, it is unclear to what extent these two concepts are indeed taken into account in basic biomedical science. To study this in a…
Chi‐Hong Tseng, Danielle Sim
Pilot studies are often the first step of experimental research. It is usually on a smaller scale and the results can inform intervention development, study feasibility and how the study implementation will play out, if such a larger main study is undertaken. This paper illustrates the relationship between pilot study…
Andrew Gelman, Amy Krefman, Lauren Kennedy, Jessica Hullman
When designing and evaluating an experiment or observational study, it is useful to have a realistic hypothesis regarding the average treatment effect. We present an approach to conceptualizing this average by first considering a distribution of effects. We demonstrate with examples in medicine, economics, and…
Hafeez Haniff, Laurent Knerr, Xiaohui Liu, Gogce Crynen + 5 more
Vascular Endothelial Growth Factor A (VEGFA) stimulates angiogenesis in human endothelial cells and increasing its expression is a potential treatment for heart failure, currently accomplished via gene or mRNA therapy. Herein, we describe a designed small molecule (TGP-377) that specifically and potently enhances VEGFA…
Timothy Gould
This study examined factors influencing student confidence and their perception of learning in the context of undergraduate chemistry and biochemistry courses. Anonymous online surveys were used to measure the extent to which small group work influenced student confidence in solving problems compared to working…
Stefan Konigorski, Christopher H. Schmid
1 Hasso Plattner Insitute for Digital Engineering, Potsdam, Germany 2 University of Potsdam, Digital Engineering Faculty, Potsdam, Germany 3 Hasso Plattner Institute for Digital Health at Mount Sinai, Icahn School of Medicine at Mount Sinai, New York, NY, USA 4 Department of Biostatistics, School of Public Health…