scholarly journals Wasted Evidence - An Assessment of the Prevalence and Determinants of Publication Bias in Africa

2018 ◽  
Author(s):  
Mercyline Kamande
Keyword(s):  
Publication Bias ◽  
Systematic Reviews ◽  
Marginal Effect ◽  
Institutional Affiliation ◽  
Level Of Education ◽  
Publication Process ◽  
Dissemination Of Research ◽  
Negative Effect ◽  
Meta Analyses ◽  
Area Of Study

The quality and credibility of evidence influence how quickly findings are absorbed in policy. Publication bias threatens the validity of research synthesis by increasing the likelihood of false positives in individual studies, systematic reviews, and meta-analyses. Given that systematic reviews and meta-analyses are likely to influence policy decisions, complete reporting of research results and dissemination of research evidence are critical. This exploratory study investigated the rate of publication among African researchers, as well as the prevalence of publication bias and factors that contribute to it. The study sought to (i) establish the rate and determinants of research publication and (ii) test a methodology to quantitatively analyse publication bias using indices constructed with qualitative information relating to the publication process. Determinants of the rate of publication were found to be age, level of education, institutional affiliation, area of study and source of funding with level of education being the most important, followed by institutional affiliation and source of funding. PhD education level has the highest impact on the rate of publication with a marginal effect of 1.24 followed by area of study with a marginal effect of 1.14. The most important driver of significant results was the methodology index where the more sound the methodology, the more likely to obtain significant results. There was a positive effect of researcher perception on the probability of obtaining significant results and a negative effect of researcher quality on the same probability. Perception of the publication process, as well as poor methodology, are likely to increase the file drawer problem.

An Analysis of “Publication Bias” in the Travel, Tourism, and Hospitality Research

2017 ◽  
Vol 6 (4) ◽  
pp. 19-37
Author(s):  
Atila Yüksel ◽  
Ekrem Tufan
Keyword(s):  
Publication Bias ◽  
Systematic Reviews ◽  
Research Articles ◽  
Null Results ◽  
Tourism And Hospitality ◽  
Meta Analyses

This article examines whether studies with favorable or statistically significant outcomes are more likely to be published than studies with null results. Should such a publication tendency be in the form of favoring significant findings exist, then the integrity of science, suggestions and conclusions becomes controversial. This also includes those particularly drawn from meta-analyses and systematic reviews. Drawing on a sample of research articles, an examination was undertaken to determine whether studies reporting significant findings were published more. Additional analyses were conducted to examine the validity of reject/support decisions in relation to null hypotheses tested in these studies. The share of the published articles, in which null hypotheses were rejected, was found to be much larger (81%). Interestingly however, calculated power levels and actual samples sizes of these studies were too small to confidently reject/support null hypotheses. Implications for research are discussed in the concluding section of the article.

Is grey literature essential for a better control of publication bias in psychiatry? An example from three meta-analyses of schizophrenia

2005 ◽  
Vol 20 (8) ◽  
pp. 550-553 ◽  
Author(s):  
José Luis R. Martin ◽  
Víctor Pérez ◽  
Montse Sacristán ◽  
Enric Álvarez
Keyword(s):  
Publication Bias ◽  
Systematic Reviews ◽  
Meta Analysis ◽  
Grey Literature ◽  
Risk Of Bias ◽  
Medical Databases ◽  
Study Results ◽  
Heterogeneous Nature ◽  
Meta Analyses ◽  
Literature Material

AbstractSystematic reviews in mental health have become useful tools for health professionals in view of the massive amount and heterogeneous nature of biomedical information available today. In order to determine the risk of bias in the studies evaluated and to avoid bias in generalizing conclusions from the reviews it is therefore important to use a very strict methodology in systematic reviews. One bias which may affect the generalization of results is publication bias, which is determined by the nature and direction of the study results. To control or minimize this type of bias, the authors of systematic reviews undertake comprehensive searches of medical databases and expand on the findings, often undertaking searches of grey literature (material which is not formally published). This paper attempts to show the consequences (and risk) of generalizing the implications of grey literature in the control of publication bias, as was proposed in a recent systematic work. By repeating the analyses for the same outcome from three different systematic reviews that included both published and grey literature our results showed that confusion between grey literature and publication bias may affect the results of a concrete meta-analysis.

scholarly journals Publication Bias in Meta-Analyses from Psychology and Medicine: A Meta-Meta-Analysis

2017 ◽  
Author(s):  
Robbie Cornelis Maria van Aert ◽  
Jelte M. Wicherts ◽  
Marcel A. L. M. van Assen
Keyword(s):  
Publication Bias ◽  
Systematic Reviews ◽  
Large Scale ◽  
Effect Sizes ◽  
Psychological Bulletin ◽  
Data Set ◽  
Monte Carlo Simulation Study ◽  
True Effect Size ◽  
Meta Analyses ◽  
Psychology And Medicine

Publication bias is a substantial problem for the credibility of research in general and of meta-analyses in particular, as it yields overestimated effects and may suggest the existence of non-existing effects. Although there is consensus that publication bias exists, how strongly it affects different scientific literatures is currently less well-known. We examined evidence of publication bias in a large-scale data set of primary studies that were included in 83 meta-analyses published in Psychological Bulletin (representing meta-analyses from psychology) and 499 systematic reviews from the Cochrane Database of Systematic Reviews (CDSR; representing meta-analyses from medicine). Publication bias was assessed on all homogeneous subsets (3.8% of all subsets of meta-analyses published in Psychological Bulletin) of primary studies included in meta-analyses, because publication bias methods do not have good statistical properties if the true effect size is heterogeneous. The Monte-Carlo simulation study revealed that the creation of homogeneous subsets resulted in challenging conditions for publication bias methods since the number of effect sizes in a subset was rather small (median number of effect sizes equaled 6). No evidence of bias was obtained using the publication bias tests. Overestimation was minimal but statistically significant, providing evidence of publication bias that appeared to be similar in both fields. These and other findings, in combination with the small percentages of statistically significant primary effect sizes (28.9% and 18.9% for subsets published in Psychological Bulletin and CDSR), led to the conclusion that evidence for publication bias in the studied homogeneous subsets is weak, but suggestive of mild publication bias in both psychology and medicine.

Clinical trial registry use in minimally invasive surgical oncology systematic reviews and meta-analyses

2019 ◽  
Vol 25 (2) ◽  
pp. 1.1-2
Author(s):  
Kaleb Fuller ◽  
Aaron Bowers ◽  
Matt Vassar
Keyword(s):  
Clinical Trial ◽  
Minimally Invasive ◽  
Publication Bias ◽  
Systematic Reviews ◽  
Clinical Decision Making ◽  
Surgical Oncology ◽  
Trial Registry ◽  
Clinical Trial Registry ◽  
Minimally Invasive Surgical ◽  
Meta Analyses

Publication bias can arise in systematic reviews when unpublished data are omitted and lead to inaccurate clinical decision making and adverse clinical outcomes. By conducting searches of clinical trial registries (CTRs), researchers can create more accurate systematic reviews and mitigate the risk of publication bias. The aims of this study are: to evaluate CTR use in systematic reviews and meta-analyses within the minimally invasive surgical oncology (MISO) literature; to conduct a search of ClinicalTrials.gov for a subset of reviews to determine if eligible trials exist that could have been used. This is a cross-sectional study of 197 systematic reviews and meta-analyses retrieved from PubMed. Of 137 included studies, 18 (13.1%) reported searching a CTR. Our ClinicalTrials.gov search revealed that of the 25 randomly selected systematic reviews that failed to conduct a trial registry search, 16 (64.0%) would have identified additional data sources. MISO systematic reviews and meta-analyses do not regularly use CTRs in their data collection, despite eligible trials being freely available.

scholarly journals Index of Independence

2019 ◽  
Vol 2 (2) ◽  
pp. p1
Author(s):  
Ilija Barukčić
Keyword(s):  
Publication Bias ◽  
Study Design ◽  
Systematic Reviews ◽  
Meta Analysis ◽  
Scientific Research ◽  
Thought Experiments ◽  
Statistical Measures ◽  
Degree Of Certainty ◽  
Meta Analyses

Objective. Under certain circumstances, the results of multiple investigations – particularly, rigorously-designed trials, can be summarized by systematic reviews and meta-analyses. However, the results of properly conducted meta-analyses can but need not be stronger than single investigations, if (publication) bias is not considered to a necessary extent. Methods. In assessing the significance of publication bias due to study design simple to handle statistical measures for quantifying publication bias are developed and discussed which can be used as a characteristic of a meta-analysis. In addition, these measures may permit comparisons of publication biases between different meta-analyses. Results. Various properties and the performance of the new measures of publication bias are studied and illustrated using simulations and clearly described thought experiments. As a result, individual studies can be reviewed with a higher degree of certainty. Conclusions. Publication bias due to study design is a serious problem in scientific research, which can affect the validity and generalization of conclusions. The index of unfairness and the index of independence are of use to quantify publication bias and to improve the quality of systematic reviews and meta-analyses.

Publication bias in meta-analyses from the Cochrane Database of Systematic Reviews

2015 ◽  
Vol 34 (20) ◽  
pp. 2781-2793 ◽  
Author(s):  
Michal Kicinski ◽  
David A. Springate ◽  
Evangelos Kontopantelis
Keyword(s):  
Publication Bias ◽  
Systematic Reviews ◽  
Cochrane Database ◽  
Meta Analyses

Publication Bias and Nonreporting Found in Majority of Systematic Reviews and Meta-analyses in Anesthesiology Journals

2016 ◽  
Vol 123 (4) ◽  
pp. 1018-1025 ◽  
Author(s):  
Riley J. Hedin ◽  
Blake A. Umberham ◽  
Byron N. Detweiler ◽  
Lauren Kollmorgen ◽  
Matt Vassar
Keyword(s):  
Publication Bias ◽  
Systematic Reviews ◽  
Meta Analyses
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