共查询到20条相似文献，搜索用时 329 毫秒
1.
Background
The removal of outliers to acquire a significant result is a questionable research practice that appears to be commonly used in psychology. In this study, we investigated whether the removal of outliers in psychology papers is related to weaker evidence (against the null hypothesis of no effect), a higher prevalence of reporting errors, and smaller sample sizes in these papers compared to papers in the same journals that did not report the exclusion of outliers from the analyses.Methods and Findings
We retrieved a total of 2667 statistical results of null hypothesis significance tests from 153 articles in main psychology journals, and compared results from articles in which outliers were removed (N = 92) with results from articles that reported no exclusion of outliers (N = 61). We preregistered our hypotheses and methods and analyzed the data at the level of articles. Results show no significant difference between the two types of articles in median p value, sample sizes, or prevalence of all reporting errors, large reporting errors, and reporting errors that concerned the statistical significance. However, we did find a discrepancy between the reported degrees of freedom of t tests and the reported sample size in 41% of articles that did not report removal of any data values. This suggests common failure to report data exclusions (or missingness) in psychological articles.Conclusions
We failed to find that the removal of outliers from the analysis in psychological articles was related to weaker evidence (against the null hypothesis of no effect), sample size, or the prevalence of errors. However, our control sample might be contaminated due to nondisclosure of excluded values in articles that did not report exclusion of outliers. Results therefore highlight the importance of more transparent reporting of statistical analyses. 相似文献2.
Background
Self-administration of medicines is believed to increase patients'' understanding about their medication and to promote their independence and autonomy in the hospital setting. The effect of inpatient self-administration of medication (SAM) schemes on patients, staff and institutions is currently unclear.Objective
To systematically review the literature relating to the effect of SAM schemes on the following outcomes: patient knowledge, patient compliance/medication errors, success in self-administration, patient satisfaction, staff satisfaction, staff workload, and costs.Design
Keyword and text word searches of online databases were performed between January and March 2013. Included articles described and evaluated inpatient SAM schemes. Case studies and anecdotal studies were excluded.Results
43 papers were included for final analysis. Due to the heterogeneity of results and unclear findings it was not possible to perform a quantitative synthesis of results. Participation in SAM schemes often led to increased knowledge about drugs and drug regimens, but not side effects. However, the effect of SAM schemes on patient compliance/medication errors was inconclusive. Patients and staff were highly satisfied with their involvement in SAM schemes.Conclusions
SAM schemes appear to provide some benefits (e.g. increased patient knowledge), but their effect on other outcomes (e.g. compliance) is unclear. Few studies of high methodological quality using validated outcome measures exist. Inconsistencies in both measuring and reporting outcomes across studies make it challenging to compare results and draw substantive conclusions about the effectiveness of SAM schemes. 相似文献3.
Background
Epigenome-wide association studies of human disease and other quantitative traits are becoming increasingly common. A series of papers reporting age-related changes in DNA methylation profiles in peripheral blood have already been published. However, blood is a heterogeneous collection of different cell types, each with a very different DNA methylation profile.Results
Using a statistical method that permits estimating the relative proportion of cell types from DNA methylation profiles, we examine data from five previously published studies, and find strong evidence of cell composition change across age in blood. We also demonstrate that, in these studies, cellular composition explains much of the observed variability in DNA methylation. Furthermore, we find high levels of confounding between age-related variability and cellular composition at the CpG level.Conclusions
Our findings underscore the importance of considering cell composition variability in epigenetic studies based on whole blood and other heterogeneous tissue sources. We also provide software for estimating and exploring this composition confounding for the Illumina 450k microarray. 相似文献4.
5.
6.
Background
We investigated whether there had been an improvement in quality of reporting for randomised controlled trials of acupuncture since the publication of the STRICTA and CONSORT statements. We conducted a before-and-after study, comparing ratings for quality of reporting following the publication of both STRICTA and CONSORT recommendations.Methodology and Principal Findings
Ninety peer reviewed journal articles reporting the results of acupuncture trials were selected at random from a wider sample frame of 266 papers. Papers published in three distinct time periods (1994–1995, 1999–2000 and 2004–2005) were compared. Assessment criteria were developed directly from CONSORT and STRICTA checklists. Papers were independently assessed for quality of reporting by two assessors, one of whom was blind to information which could have introduced systematic bias (e.g. date of publication). We detected a statistically significant increase in the reporting of CONSORT items for papers published in each time period measured. We did not, however, find a difference between the number of STRICTA items reported in journal articles published before and 3 to 4 years following the introduction of STRICTA recommendations.Conclusions and Significance
The results of this study suggest that general standards of reporting for acupuncture trials have significantly improved since the introduction of the CONSORT statement in 1996, but that quality in reporting details specific to acupuncture interventions has yet to change following the more recent introduction of STRICTA recommendations. Wider targeting and revision of the guidelines is recommended. 相似文献7.
Background
Many journals now require authors share their data with other investigators, either by depositing the data in a public repository or making it freely available upon request. These policies are explicit, but remain largely untested. We sought to determine how well authors comply with such policies by requesting data from authors who had published in one of two journals with clear data sharing policies.Methods and Findings
We requested data from ten investigators who had published in either PLoS Medicine or PLoS Clinical Trials. All responses were carefully documented. In the event that we were refused data, we reminded authors of the journal''s data sharing guidelines. If we did not receive a response to our initial request, a second request was made. Following the ten requests for raw data, three investigators did not respond, four authors responded and refused to share their data, two email addresses were no longer valid, and one author requested further details. A reminder of PLoS''s explicit requirement that authors share data did not change the reply from the four authors who initially refused. Only one author sent an original data set.Conclusions
We received only one of ten raw data sets requested. This suggests that journal policies requiring data sharing do not lead to authors making their data sets available to independent investigators. 相似文献8.
Objective
A systematic review was conducted to identify and quality assess how studies published since 1999 have measured and reported the usage of hearing aids in older adults. The relationship between usage and other dimensions of hearing aid outcome, age and hearing loss are summarised.Data sources
Articles were identified through systematic searches in PubMed/MEDLINE, The University of Nottingham Online Catalogue, Web of Science and through reference checking. Study eligibility criteria: (1) participants aged fifty years or over with sensori-neural hearing loss, (2) provision of an air conduction hearing aid, (3) inclusion of hearing aid usage measure(s) and (4) published between 1999 and 2011.Results
Of the initial 1933 papers obtained from the searches, a total of 64 were found eligible for review and were quality assessed on six dimensions: study design, choice of outcome instruments, level of reporting (usage, age, and audiometry) and cross validation of usage measures. Five papers were rated as being of high quality (scoring 10–12), 35 papers were rated as being of moderate quality (scoring 7–9), 22 as low quality (scoring 4–6) and two as very low quality (scoring 0–2). Fifteen different methods were identified for assessing the usage of hearing aids.Conclusions
Generally, the usage data reviewed was not well specified. There was a lack of consistency and robustness in the way that usage of hearing aids was assessed and categorised. There is a need for more standardised level of reporting of hearing aid usage data to further understand the relationship between usage and hearing aid outcomes. 相似文献9.
10.
Background
Evidence about relevant outcomes is required in the evaluation of clinical interventions for children with autism spectrum disorders (ASD). However, to date, the variety of outcome measurement tools being used, and lack of knowledge about the measurement properties of some, compromise conclusions regarding the most effective interventions.Objectives
This two-stage systematic review aimed to identify the tools used in studies evaluating interventions for anxiety for high-functioning children with ASD in middle childhood, and then to evaluate the tools for their appropriateness and measurement properties.Methods
Electronic databases including Medline, PsychInfo, Embase, and the Cochrane database and registers were searched for anxiety intervention studies for children with ASD in middle childhood. Articles examining the measurement properties of the tools used were then searched for using a methodological filter in PubMed, and the quality of the papers evaluated using the COSMIN checklist.Results
Ten intervention studies were identified in which six tools measuring anxiety and one of overall symptom change were used as primary outcomes. One further tool was included as it is recommended for standard use in UK children''s mental health services. Sixty three articles on the properties of the tools were evaluated for the quality of evidence, and the quality of the measurement properties of each tool was summarised.Conclusions
Overall three questionnaires were found robust in their measurement properties, the Spence Children''s Anxiety Scale, its revised version – the Revised Children''s Anxiety and Depression Scale, and also the Screen for Child Anxiety Related Emotional Disorders. Crucially the articles on measurement properties provided almost no evidence on responsiveness to change, nor on the validity of use of the tools for evaluation of interventions for children with ASD.PROSPERO Registration number
CRD42012002684. 相似文献11.
Flandre P 《PloS one》2011,6(9):e22871
Background
In recent years the “noninferiority” trial has emerged as the new standard design for HIV drug development among antiretroviral patients often with a primary endpoint based on the difference in success rates between the two treatment groups. Different statistical methods have been introduced to provide confidence intervals for that difference. The main objective is to investigate whether the choice of the statistical method changes the conclusion of the trials.Methods
We presented 11 trials published in 2010 using a difference in proportions as the primary endpoint. In these trials, 5 different statistical methods have been used to estimate such confidence intervals. The five methods are described and applied to data from the 11 trials. The noninferiority of the new treatment is not demonstrated if the prespecified noninferiority margin it includes in the confidence interval of the treatment difference.Results
Results indicated that confidence intervals can be quite different according to the method used. In many situations, however, conclusions of the trials are not altered because point estimates of the treatment difference were too far from the prespecified noninferiority margins. Nevertheless, in few trials the use of different statistical methods led to different conclusions. In particular the use of “exact” methods can be very confusing.Conclusion
Statistical methods used to estimate confidence intervals in noninferiority trials have a strong impact on the conclusion of such trials. 相似文献12.
Background
The reporting of outcomes within published randomized trials has previously been shown to be incomplete, biased and inconsistent with study protocols. We sought to determine whether outcome reporting bias would be present in a cohort of government-funded trials subjected to rigorous peer review.Methods
We compared protocols for randomized trials approved for funding by the Canadian Institutes of Health Research (formerly the Medical Research Council of Canada) from 1990 to 1998 with subsequent reports of the trials identified in journal publications. Characteristics of reported and unreported outcomes were recorded from the protocols and publications. Incompletely reported outcomes were defined as those with insufficient data provided in publications for inclusion in meta-analyses. An overall odds ratio measuring the association between completeness of reporting and statistical significance was calculated stratified by trial. Finally, primary outcomes specified in trial protocols were compared with those reported in publications.Results
We identified 48 trials with 68 publications and 1402 outcomes. The median number of participants per trial was 299, and 44% of the trials were published in general medical journals. A median of 31% (10th–90th percentile range 5%–67%) of outcomes measured to assess the efficacy of an intervention (efficacy outcomes) and 59% (0%–100%) of those measured to assess the harm of an intervention (harm outcomes) per trial were incompletely reported. Statistically significant efficacy outcomes had a higher odds than nonsignificant efficacy outcomes of being fully reported (odds ratio 2.7; 95% confidence interval 1.5–5.0). Primary outcomes differed between protocols and publications for 40% of the trials.Interpretation
Selective reporting of outcomes frequently occurs in publications of high-quality government-funded trials.Selective reporting of results from randomized trials can occur either at the level of end points within published studies (outcome reporting bias)1 or at the level of entire trials that are selectively published (study publication bias).2 Outcome reporting bias has previously been demonstrated in a broad cohort of published trials approved by a regional ethics committee.1 The Canadian Institutes of Health Research (CIHR) — the primary federal funding agency, known before 2000 as the Medical Research Council of Canada (MRC) — recognized the need to address this issue and conducted an internal review process in 2002 to evaluate the reporting of results from its funded trials. The primary objectives were to determine (a) the prevalence of incomplete outcome reporting in journal publications of randomized trials; (b) the degree of association between adequate outcome reporting and statistical significance; and (c) the consistency between primary outcomes specified in trial protocols and those specified in subsequent journal publications. 相似文献13.
Dwueng-Chwuan Jhwueng 《PloS one》2013,8(6)
Background
Phylogenetic comparative methods (PCMs) have been applied widely in analyzing data from related species but their fit to data is rarely assessed.Question
Can one determine whether any particular comparative method is typically more appropriate than others by examining comparative data sets?Data
I conducted a meta-analysis of 122 phylogenetic data sets found by searching all papers in JEB, Blackwell Synergy and JSTOR published in 2002–2005 for the purpose of assessing the fit of PCMs. The number of species in these data sets ranged from 9 to 117.Analysis Method
I used the Akaike information criterion to compare PCMs, and then fit PCMs to bivariate data sets through REML analysis. Correlation estimates between two traits and bootstrapped confidence intervals of correlations from each model were also compared.Conclusions
For phylogenies of less than one hundred taxa, the Independent Contrast method and the independent, non-phylogenetic models provide the best fit.For bivariate analysis, correlations from different PCMs are qualitatively similar so that actual correlations from real data seem to be robust to the PCM chosen for the analysis. Therefore, researchers might apply the PCM they believe best describes the evolutionary mechanisms underlying their data. 相似文献14.
Background
HIV-related outcomes may be affected by biological sex and by pregnancy. Including women in general and pregnant women in particular in HIV-related research is important for generalizability of findings.Objective
To characterize representation of pregnant and non-pregnant women in HIV-related research conducted in general populations.Data Sources
All HIV-related articles published in fifteen journals from January to March of 2011. We selected the top five journals by 2010 impact factor, in internal medicine, infectious diseases, and HIV/AIDS.Study Eligibility Criteria
HIV-related studies reporting original research on questions applicable to both men and women of reproductive age were considered; studies were excluded if they did not include individual-level patient data.Study appraisal and synthesis methods.
Articles were doubly reviewed and abstracted; discrepancies were resolved through consensus. We recorded proportion of female study participants, whether pregnant women were included or excluded, and other key factors.Results
In total, 2014 articles were published during this period. After screening, 259 articles were included as original HIV-related research reporting individual-level data; of these, 226 were determined to be articles relevant to both men and women of reproductive age. In these articles, women were adequately represented within geographic region. The vast majority of published articles, 183/226 (81%), did not mention pregnancy (or related issues); still fewer included pregnant women (n=33), reported numbers of pregnant women (n=19), or analyzed using pregnancy status (n=9).Limitations
Data were missing for some key variables, including pregnancy. The time period over which published works were evaluated was relatively short.Conclusions and implications of key findings.
The under-reporting and inattention to pregnancy in the HIV literature may reduce policy-makers’ ability to set evidence-based policy around HIV/AIDS care for pregnant women and women of child-bearing age. 相似文献15.
Background
Use of a risk of bias (ROB) tool has been encouraged and advocated to reviewers writing systematic reviews (SRs) and meta-analyses (MAs). Selective outcome reporting and other sources of bias are included in the Cochrane ROB tool. It is important to know how this specific tool for assessing ROB has been applied since its release. Our objectives were to evaluate whether and to what extent the new Cochrane ROB tool has been used in Chinese journal papers of acupuncture.Methods
We searched CBM, TCM database, CJFD, CSJD, and the Wanfang Database from inception to March 2011. Two reviewers independently selected SRs that primarily focused on acupuncture and moxibustion, from which the data was extracted and analyzed.Results
A total of 836 SRs were identified from the search, of which, 105 were included and four are awaiting assessment. Thirty-six of the 105 SRs were published before release of the Cochrane ROB tool (up to 2009). Most used the Cochrane Handbook 4.2 or Jadad''s scale for risk or quality assessment. From 2009 to March 2011 69 SRs were identified. While “risk of bias” was reported for approximately two-thirds of SRs, only two SRs mentioned use of a “risk of bias tool” in their assessment. Only 5.8% (4/69) of reviews reported information on all six domains which are involved in the ROB tool. A risk of bias graph/summary figure was provided in 2.9% (2/69) of reviews. Most SRs gave information about sequence generation, allocation concealment, blindness, and incomplete outcome data, however, few reviews (5.8%; 4/69) described selective reporting or other potential sources of bias.Conclusions
The Cochrane “risk of bias” tool has not been used in all SRs/MAs of acupuncture published in Chinese Journals after 2008. When the ROB tool was used, reporting of relevant information was often incomplete. 相似文献16.
Qing Guo Melissa Parlar Wanda Truong Geoffrey Hall Lehana Thabane Margaret McKinnon Ron Goeree Eleanor Pullenayegum 《PloS one》2014,9(4)
Introduction
Complete reporting assists readers in confirming the methodological rigor and validity of findings and allows replication. The reporting quality of observational functional magnetic resonance imaging (fMRI) studies involving clinical participants is unclear.Objectives
We sought to determine the quality of reporting in observational fMRI studies involving clinical participants.Methods
We searched OVID MEDLINE for fMRI studies in six leading journals between January 2010 and December 2011.Three independent reviewers abstracted data from articles using an 83-item checklist adapted from the guidelines proposed by Poldrack et al. (Neuroimage 2008; 40: 409–14). We calculated the percentage of articles reporting each item of the checklist and the percentage of reported items per article.Results
A random sample of 100 eligible articles was included in the study. Thirty-one items were reported by fewer than 50% of the articles and 13 items were reported by fewer than 20% of the articles. The median percentage of reported items per article was 51% (ranging from 30% to 78%). Although most articles reported statistical methods for within-subject modeling (92%) and for between-subject group modeling (97%), none of the articles reported observed effect sizes for any negative finding (0%). Few articles reported justifications for fixed-effect inferences used for group modeling (3%) and temporal autocorrelations used to account for within-subject variances and correlations (18%). Other under-reported areas included whether and how the task design was optimized for efficiency (22%) and distributions of inter-trial intervals (23%).Conclusions
This study indicates that substantial improvement in the reporting of observational clinical fMRI studies is required. Poldrack et al.''s guidelines provide a means of improving overall reporting quality. Nonetheless, these guidelines are lengthy and may be at odds with strict word limits for publication; creation of a shortened-version of Poldrack''s checklist that contains the most relevant items may be useful in this regard. 相似文献17.
Elodie Le Fourn Bruno Giraudeau Olivier Chosidow Marie-Sylvie Doutre Gérard Lorette 《PloS one》2013,8(8)
Background
The recommended first-line therapy of chronic urticaria is second-generation antihistamines, but the modalities of treatment remains unclear. Numerous recommendations with heterogeneous conclusions have been published. We wondered whether such heterogeneous conclusions were linked to the quality of published studies and their reporting.Objective
To review the study design and quality of reporting of randomized control trials investigating pharmacological treatment of autoimmune or idiopathic chronic urticaria.Methodology/Principal Findings
MEDLINE and EMBASE were searched for pharmacological randomized controlled trials involving patients with chronic autoimmune or idiopathic urticaria, with the main outcome being treatment efficacy. Data were collected on general characteristics of the studies, internal validity, studied treatments, design of the trial, outcome measures and “spin” strategy in interpreting results. Spin was defined as use of specific reporting strategies to highlight that the experimental treatment is beneficial, despite statistically nonsignificant results. We evaluated 52 articles that met our criteria. Patients were reported as blinded in 42 articles (81%) and the outcome assessor was blinded in 37 (71%). A placebo was the only comparator in 13 (25%) studies. The study duration was <8 weeks in 39 articles (75%), with no follow-up after discontinuation of treatment in 37 (71%). In 4 articles (8%), blinding was clear because they described blinding of the outcome assessor, the treatment was not recognizable (identical or double-dummy) or had no major secondary effects, and computed randomization was centralized. The primary outcome was specified in 33 articles (63%) and was a score in 31. In total, 15 different scores were used. A spin strategy was used for 10 of 12 studies with a nonsignificant primary outcome.Conclusion
For establishing guidelines in treatment of chronic urticaria, studies should focus on choosing clinically relevant and reproducible primary outcomes, long-term follow-up, limited use of placebo and avoiding spin strategies. 相似文献18.
Kerry Dwan Douglas G. Altman Mike Clarke Carrol Gamble Julian P. T. Higgins Jonathan A. C. Sterne Paula R. Williamson Jamie J. Kirkham 《PLoS medicine》2014,11(6)
Background
Most publications about selective reporting in clinical trials have focussed on outcomes. However, selective reporting of analyses for a given outcome may also affect the validity of findings. If analyses are selected on the basis of the results, reporting bias may occur. The aims of this study were to review and summarise the evidence from empirical cohort studies that assessed discrepant or selective reporting of analyses in randomised controlled trials (RCTs).Methods and Findings
A systematic review was conducted and included cohort studies that assessed any aspect of the reporting of analyses of RCTs by comparing different trial documents, e.g., protocol compared to trial report, or different sections within a trial publication. The Cochrane Methodology Register, Medline (Ovid), PsycInfo (Ovid), and PubMed were searched on 5 February 2014. Two authors independently selected studies, performed data extraction, and assessed the methodological quality of the eligible studies. Twenty-two studies (containing 3,140 RCTs) published between 2000 and 2013 were included. Twenty-two studies reported on discrepancies between information given in different sources. Discrepancies were found in statistical analyses (eight studies), composite outcomes (one study), the handling of missing data (three studies), unadjusted versus adjusted analyses (three studies), handling of continuous data (three studies), and subgroup analyses (12 studies). Discrepancy rates varied, ranging from 7% (3/42) to 88% (7/8) in statistical analyses, 46% (36/79) to 82% (23/28) in adjusted versus unadjusted analyses, and 61% (11/18) to 100% (25/25) in subgroup analyses. This review is limited in that none of the included studies investigated the evidence for bias resulting from selective reporting of analyses. It was not possible to combine studies to provide overall summary estimates, and so the results of studies are discussed narratively.Conclusions
Discrepancies in analyses between publications and other study documentation were common, but reasons for these discrepancies were not discussed in the trial reports. To ensure transparency, protocols and statistical analysis plans need to be published, and investigators should adhere to these or explain discrepancies. Please see later in the article for the Editors'' Summary 相似文献19.
Purpose
In the developed countries, the incidence of esophageal adenocarcinoma (EAC) is increasing over recent decades. The purpose of this meta-analysis was to arrive at quantitative conclusions about the contribution of alcohol intakes and the progression of Barrett''s esophagus.Methods
A comprehensive, systematic bibliographic search of medical literature published up to Oct 2013 was conducted to identify relevant studies. A meta-analysis was conducted for alcohol consumption on the Barrett''s esophagus progression.Results
A total of 882 cases in 6,867 individuals from 14 observational studies were indemnified in this meta-analysis. The result of this current meta-analysis, including 10 case-control and 4 cohort studies, indicated that alcohol consumption was not associated with the neoplastic progression in Barrett''s esophagus (RR, 1.17; 95% CI, 0.93–1.48). When stratified by the study designs, no significant association was detected in either high vs low group or ever vs never group.Conclusions
Alcohol drinking is not associated with risk of neoplastic progression in Barrett''s esophagus. Further well designed studies are needed in this area. 相似文献20.