scholarly journals Using Selection Models to Assess Sensitivity to Publication Bias: A Tutorial and Call for More Routine Use

2021 ◽  
Author(s):  
Maximilian Maier ◽  
Tyler VanderWeele ◽  
Maya B Mathur

In meta-analyses, it is critical to assess the extent to which publication bias might have compromised the results. Classical methods based on the funnel plot, including Egger’s test and Trim-and-Fill, have become the de facto default methods to do so, with a large majority of recent meta-analyses in top medical journals (85%) assessing for publication bias exclusively using these methods. However, these classical funnel plot methods have important limitations when used as the sole means of assessing publication bias: they essentially assume that the publication process favors large point estimates for small studies and does not affect the largest studies, and they can perform poorly when effects are heterogeneous. In light of these limitations, we recommend that meta-analyses routinely apply other publication bias methods in addition to or instead of classical funnel plot methods. To this end, we describe how to use and interpret selection models. These methods make the often more realistic assumption that publication bias favors ``statistically significant'' results and that also directly accommodate effect heterogeneity. Selection models are well-established in the statistics literature and are supported by user-friendly software, yet remain rarely reported in many disciplines. We use previously published meta-analyses to demonstrate that selection models can yield insights that extend beyond those provided by funnel plot methods, suggesting the importance of establishing more comprehensive reporting practices for publication bias assessment.

2021 ◽  
Vol 5 (1) ◽  
pp. e100135
Author(s):  
Xue Ying Zhang ◽  
Jan Vollert ◽  
Emily S Sena ◽  
Andrew SC Rice ◽  
Nadia Soliman

ObjectiveThigmotaxis is an innate predator avoidance behaviour of rodents and is enhanced when animals are under stress. It is characterised by the preference of a rodent to seek shelter, rather than expose itself to the aversive open area. The behaviour has been proposed to be a measurable construct that can address the impact of pain on rodent behaviour. This systematic review will assess whether thigmotaxis can be influenced by experimental persistent pain and attenuated by pharmacological interventions in rodents.Search strategyWe will conduct search on three electronic databases to identify studies in which thigmotaxis was used as an outcome measure contextualised to a rodent model associated with persistent pain. All studies published until the date of the search will be considered.Screening and annotationTwo independent reviewers will screen studies based on the order of (1) titles and abstracts, and (2) full texts.Data management and reportingFor meta-analysis, we will extract thigmotactic behavioural data and calculate effect sizes. Effect sizes will be combined using a random-effects model. We will assess heterogeneity and identify sources of heterogeneity. A risk-of-bias assessment will be conducted to evaluate study quality. Publication bias will be assessed using funnel plots, Egger’s regression and trim-and-fill analysis. We will also extract stimulus-evoked limb withdrawal data to assess its correlation with thigmotaxis in the same animals. The evidence obtained will provide a comprehensive understanding of the strengths and limitations of using thigmotactic outcome measure in animal pain research so that future experimental designs can be optimised. We will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines and disseminate the review findings through publication and conference presentation.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Mistire Teshome Guta ◽  
Tiwabwork Tekalign ◽  
Nefsu Awoke ◽  
Robera Olana Fite ◽  
Getahun Dendir ◽  
...  

Aims. This systemic review and meta-analysis were aimed at determining the level of anxiety and depression among cystic fibrosis patients in the world. Methods. We conducted a systematic search of published studies from PubMed, EMBASE, MEDLINE, Cochrane, Scopus, Web of Science, CINAHL, and manually on Google Scholar. This meta-analysis follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The quality of studies was assessed by the modified Newcastle-Ottawa Scale (NOS). Meta-analysis was carried out using a random-effects method using the STATA™ Version 14 software. Trim and fill analysis was done to correct the presence of significant publication bias. Result. From 419,820 obtained studies, 26 studies from 2 different parts of the world including 9766. The overall global pooled prevalence of anxiety and depression after correction for publication bias by trim and fill analysis was found to be 24.91(95% CI: 20.8-28.9) for anxiety. The subgroup analyses revealed with the lowest prevalence, 23.59%, (95% CI: 8.08, 39.09)) in North America and the highest, 26.77%, (95% CI: 22.5, 31.04) seen in Europe for anxiety and with the highest prevalence, 18.67%, (95% CI: 9.82, 27.5) in North America and the lowest, 13.27%, (95% CI: -10.05, 16.5) seen in Europe for depression. Conclusion. The global prevalence of anxiety and depression among cystic fibrosis patients is common. Therefore, close monitoring of the patient, regularly screening for anxiety and depression, and appropriate prevention techniques is recommended.


Author(s):  
Mariana Feijó ◽  
Roberta V L Martins ◽  
Sílvia Socorro ◽  
Luísa Pereira ◽  
Sara Correia

Abstract Endocrine-disrupting chemicals have become an issue of scientific and public discussion. Vinclozolin (VNZ) is a fungicide that competitively antagonizes the binding of natural androgens to their receptor, disturbing the function of tissues that are sensitive to these hormones, as is the case of the male reproductive organs. A systematic review with meta-analyses of rodent studies was conducted to answer the following question: Does exposure to VNZ affect sperm parameters and testicular/epididymal weight? The methodology was prespecified according to the Cochrane Handbook for Systematic Reviews and PRISMA recommendations. Sixteen articles met the inclusion criteria, comprising a total of 1189 animals. The risk of publication bias was assessed using the Trim and Fill adjustment, funnel plot, and Egger regression test. Heterogeneity and inconsistency across the findings were tested using the Q-statistic and I2 of Higgins, respectively. Sensitivity was also analyzed. Statistical analysis was performed on Comprehensive Meta-Analysis software (Version 2.0), using random models and weighted mean differences along with a 95% confidence interval. Sperm motility, counts, daily sperm production (evidence of publication bias), and epididymis weight were decreased in VNZ-treated animals. Exposure length and dose, as well as the time point of exposure, influenced the obtained results. Despite the moderate/high heterogeneity observed, the sensitivity analysis overall demonstrated the robustness of the findings. The quality scores of the included studies were superior to 4 in a total of 9, then classified as good. The obtained data corroborate the capability of VNZ exposure to disrupt spermatogenic output and compromise male fertility.


2021 ◽  
Vol 12 ◽  
Author(s):  
Geovan Menezes de Sousa ◽  
Vagner Deuel de Oliveira Tavares ◽  
Maria Lara Porpino de Meiroz Grilo ◽  
Monique Leite Galvão Coelho ◽  
Geissy Lainny de Lima-Araújo ◽  
...  

Background: Mental health burden has been massively reported during the COVID-19 pandemic period. Aiming to summarise these data, we present a meta-review of meta-analyses that evaluated the impact of COVID-19 pandemic on anxiety, depressive and stress symptoms, psychological distress, post-traumatic stress disorder/symptoms (PTSD), and sleep disturbance, reporting its prevalence on general public (GP) and health care workers (HCW).Methods: A search was performed in the PubMed, EMBASE, and the Web of Science. Sleep disturbances, psychological distress, stress, and burnout were grouped as “Psychophysiological stress,” and anxiety, depression, and PTSD were grouped as “Psychopathology.” A random-effects model, calculating the pooled prevalence together with 95% confidence interval was performed for each domain. Subgroup analyses were performed for each population type (GP and HCW) and for each mental health outcome. For anxiety and depression, subgroup analysis for population type was performed. Heterogeneity is reported as I2. Publication bias was assessed through visual inspection of the funnel plot, and further tested by Egger's test and trim and fill analyses.Results: A total of 18 meta-analyses were included. The prevalence of psychophysiological stress was 31.99% (CI: 26.88–37.58, I2 = 99.9%). HCW showed a higher prevalence (37.74%, CI: 33.26–42.45, I2 = 99.7%) than the GP (20.67%, 15.07–27.66, I2 = 99.9%). The overall prevalence of insomnia, psychological distress, and stress were, respectively, 32.34% (CI: 25.65–39.84), 28.25% (CI: 18.12–41.20), and 36% (CI: 29.31–43.54). Psychopathology was present at 26.45% (CI: 24.22–28.79, I2 = 99.9%) of the sample, with similar estimates for population (HCW 26.14%, CI: 23.37–29.12, I2 = 99.9%; GP: 26.99%, CI: 23.41–30.9, I2 = 99.9%). The prevalence of anxiety, depression, and PTSD was 27.77% (CI: 24.47–31.32), 26.93% (CI: 23.92–30.17), and 20% (CI: 15.54–24.37), respectively. Similar proportions between populations were found for anxiety (HCW = 27.5%, CI: 23.78–31.55; GP = 28.33%, CI: 22.1–35.5) and depression (HCW = 27.05%, CI: 23.14–31.36; GP = 26.7%, CI: 22.32–31.59). Asymmetry in the funnel plot was found, and a slight increase in the estimate of overall psychopathology (29.08%, CI: 26.42–31.89) was found after the trim and fill analysis.Conclusions: The prevalence of mental health problems ranged from 20 to 36%. HCW presented a higher prevalence of psychophysiological stress than the general population.Systematic Review Registration:https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=252221, identifier: CRD42021252221.


2017 ◽  
Author(s):  
Andreas Schneck

Background Publication bias is a form of scientific misconduct. It threatens the validity of research results and the credibility of science. Although several tests on publication bias exist, no in-depth evaluations are available that suggest which test to use for the specific research problem. Methods In the study at hand four tests on publication bias, Egger’s test (FAT), p-uniform, the test of excess significance (TES), as well as the caliper test, were evaluated in a Monte Carlo simulation. Two different types of publication bias, as well as its degree (0%, 50%, 100%), were simulated. The type of publication bias was defined either as file-drawer, meaning the repeated analysis of new datasets, or p-hacking, meaning the inclusion of covariates in order to obtain a significant result. In addition, the underlying effect (β = 0, 0.5, 1, 1.5), effect heterogeneity, and the number of observations in the simulated primary studies (N =100, 500), as well as in the number of observations for the publication bias tests (K =100, 1000), were varied. Results All tests evaluated were able to identify publication bias both in the file-drawer and p-hacking condition. The false positive rates were, with the exception of the 15%- and 20%-caliper test, unbiased. The FAT had the largest statistical power in the file-drawer conditions, whereas under p-hacking the TES was, except under effect heterogeneity, slightly better. The caliper test was, however, inferior to the other tests under effect homogeneity and had a decent statistical power only in conditions with 1000 primary studies. Discussion The FAT is recommended as a test for publication bias in standard meta-analyses with no or only small effect heterogeneity. If no clear direction of publication bias is suspected the TES is the first alternative to the FAT. The 5%-caliper tests is recommended under conditions of effect heterogeneity, which may be found if publication bias is examined in a discipline-wide setting when primary studies cover different research problems.


2019 ◽  
Vol 50 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Ioannis Angelakis ◽  
Jennifer L. Austin ◽  
Patricia Gooding

AbstractIn the past decade, the links between core types of childhood maltreatment and suicidal acts have become an increasingly important area of investigation. However, no meta-analytic review has examined this relationship in prisoners. We undertook the first systematic meta-analytic review examining the link between childhood maltreatment and suicide attempts in prisoners to redress this important gap. We searched Medline, PsychINFO, Embase, Web of Science and CINAHL from inception until August 2019. Meta-analyses using random effect models were applied, and heterogeneity was quantified using the I2 statistic. Publication bias and risk of bias across studies were assessed. We identified 24 studies comprising 16 586 prisoners. The rates of different types of childhood maltreatment ranged between 29% and 68% [95% confidence interval (CI) 18–81%]. The rate of suicide attempts in prisoners was 23% (95% CI 18–27%). Main results demonstrated that sexual abuse [odds ratio (OR) 2.68, 95% CI 1.86–3.86], physical abuse (OR 2.16, 95% CI 1.60–2.91), emotional abuse (OR 2.70, 95% CI 1.92–3.79), emotional neglect (OR 2.29, 95% CI 1.69–3.10), physical neglect (OR 1.57, 95% CI 1.27–1.94) and combined abuse (OR 3.09, 95% CI 2.14–4.45) were strongly associated with suicide attempts in prisoners. There was an indication of publication bias. Duval and Tweedie's trim-and-fill method was applied, which increased the odds for suicide attempts. Given the high rates of prison suicide deaths and suicide attempts, our findings suggest an urgent need for targeted suicide prevention priorities for prisoners, with a particular focus on ameliorating the effects of childhood traumatic experiences on suicidal prisoners.


2019 ◽  
Author(s):  
Christopher Carpenter

Publication bias can occur when a study is not published in an academic journal because the study did not find a statistically significant result. It can bias meta-analytic estimates upwards because the meta-analyses are missing studies that provide small estimates of the effect size under study. This paper describes the trim and fill technique of estimating the impact of publication bias on meta-analyses (Duval and Tweedie, 2000a, 2000b) and provides a worked example. A sample of 68 meta-analyses of communication research were tested for publication bias using the trim and fill technique. The results suggest that most communication meta-analyses are not substantially affected by publication bias.


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