39 research outputs found

    “statcheck”:Automatically detect statistical reporting inconsistencies to increase reproducibility of meta-analyses.

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    We present the R package and web app statcheck to automatically detect statistical reporting inconsistencies in primary studies and meta‐analyses. Previous research has shown a high prevalence of reported p‐values that are inconsistent ‐ meaning a re‐calculated p‐value, based on the reported test statistic and degrees of freedom, does not match the author‐reported p‐value. Such inconsistencies affect the reproducibility and evidential value of published findings. The tool statcheck can help researchers to identify statistical inconsistencies so that they may correct them. In this paper, we provide an overview of the prevalence and consequences of statistical reporting inconsistencies. We also discuss the tool statcheck in more detail and give an example of how it can be used in a meta‐analysis. We end with some recommendations concerning the use of statcheck in meta‐analyses and make a case for better reporting standards of statistical results

    Identification of nine sequence types of the 16S rRNA genes of Campylobacter jejuni subsp. jejuni isolated from broilers

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    <p>Abstract</p> <p>Background</p> <p>Campylobacter is the most commonly reported bacterial cause of enteritis in humans in the EU Member States and other industrialized countries. One significant source of infection is broilers and consumption of undercooked broiler meat. <it>Campylobacter jejuni </it>is the <it>Campylobacter </it>sp. predominantly found in infected humans and colonized broilers. Sequence analysis of the 16S rRNA gene is very useful for identification of bacteria to genus and species level. The objectives in this study were to determine the degree of intraspecific variation in the 16S rRNA genes of <it>C. jejuni </it>and <it>C. coli </it>and to determine whether the 16S rRNA sequence types correlated with genotypes generated by PFGE analysis of <it>Sma</it>I restricted genomic DNA of the strains.</p> <p>Methods</p> <p>The 16S rRNA genes of 45 strains of <it>C. jejuni </it>and two <it>C. coli </it>strains isolated from broilers were sequenced and compared with 16S rRNA sequences retrieved from the Ribosomal Database Project or GenBank. The strains were also genotyped by PFGE after digestion with <it>Sma</it>I.</p> <p>Results</p> <p>Sequence analyses of the 16S rRNA genes revealed nine sequence types of the <it>Campylobacter </it>strains and the similarities between the different sequence types were in the range 99.6–99.9%. The number of nucleotide substitutions varied between one and six among the nine 16S rRNA sequence types. One of the nine 16S rRNA sequence profiles was common to 12 of the strains from our study and two of these were identified as <it>Campylobacter coli </it>by PCR/REA. The other 10 strains were identified as <it>Campylobacter jejuni</it>. Five of the nine sequence types were also found among the <it>Campylobacter </it>sequences deposited in GenBank. The three 16S rRNA genes in the analysed strains were identical within each individual strain for all 47 strains.</p> <p>Conclusion</p> <p><it>C. jejuni </it>and <it>C. coli </it>seem to lack polymorphisms in their 16S rRNA gene, but phylogenetic analysis based on 16S rRNA sequences was not always sufficient for differentiation between <it>C. jejuni </it>and <it>C. coli</it>. The strains were grouped in two major clusters according to 16S rRNA, one cluster with only <it>C. jejuni </it>and the other with both <it>C. jejuni </it>and <it>C. coli</it>. Genotyping of the 47 strains by PFGE after digestion with <it>Sma</it>I resulted in 22 subtypes. A potential correlation was found between the <it>Sma</it>I profiles and the 16S rRNA sequences, as a certain <it>Sma</it>I type only appeared in one of the two major phylogenetic groups.</p

    Education is associated with lower levels of abdominal obesity in women with a non-agricultural occupation: an interaction study using China's Four Provinces survey.

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    The prevalence of obesity is increasing rapidly in low- and middle-income countries (LMICs) as their populations become exposed to obesogenic environments. The transition from an agrarian to an industrial and service-based economy results in important lifestyle changes. Yet different socioeconomic groups may experience and respond to these changes differently. Investigating the socioeconomic distribution of obesity in LMICs is key to understanding the causes of obesity but the field is limited by the scarcity of data and a uni-dimensional approach to socioeconomic status (SES). This study splits socioeconomic status into two dimensions to investigate how educated women may have lower levels of obesity in a context where labour market opportunities have shifted away from agriculture to other forms of employment. The Four Provinces Study in China 2008/09 is a household-based community survey of 4,314 people aged ≄60  years (2,465 women). It was used to investigate an interaction between education (none/any) and occupation (agricultural/non-agricultural) on high-risk central obesity defined as a waist circumference ≄80 cm. An interaction term between education and occupation was incorporated in a multivariate logistic regression model, and the estimates adjusted for age, parity, urban/rural residence and health behaviours (smoking, alcohol, meat and fruit & vegetable consumption). Complete case analyses were undertaken and results confirmed using multiple imputation to impute missing data. An interaction between occupation and education was present (P = 0.02). In the group with no education, the odds of central obesity in the sedentary occupation group were more than double those of the agricultural occupation group even after taking age group and parity into account (OR; 95%CI: 2.21; 1.52, 3.21), while in the group with any education there was no evidence of such a relationship (OR; 95%CI: 1.25; 0.92, 1.70). Health behaviours appeared to account for some of the association. These findings suggest that education may have a protective role in women against the higher odds of obesity associated with occupational shifts in middle-income countries, and that investment in women's education may present an important long term investment in obesity prevention. Further research could elucidate the mechanisms behind this association

    The influence of journal submission guidelines on authors' reporting of statistics and use of open research practices.

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    From January 2014, Psychological Science introduced new submission guidelines that encouraged the use of effect sizes, estimation, and meta-analysis (the "new statistics"), required extra detail of methods, and offered badges for use of open science practices. We investigated the use of these practices in empirical articles published by Psychological Science and, for comparison, by the Journal of Experimental Psychology: General, during the period of January 2013 to December 2015. The use of null hypothesis significance testing (NHST) was extremely high at all times and in both journals. In Psychological Science, the use of confidence intervals increased markedly overall, from 28% of articles in 2013 to 70% in 2015, as did the availability of open data (3 to 39%) and open materials (7 to 31%). The other journal showed smaller or much smaller changes. Our findings suggest that journal-specific submission guidelines may encourage desirable changes in authors' practices

    A many-analysts approach to the relation between religiosity and well-being

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    The relation between religiosity and well-being is one of the most researched topics in the psychology of religion, yet the directionality and robustness of the effect remains debated. Here, we adopted a many-analysts approach to assess the robustness of this relation based on a new cross-cultural dataset (N=10,535 participants from 24 countries). We recruited 120 analysis teams to investigate (1) whether religious people self-report higher well-being, and (2) whether the relation between religiosity and self-reported well-being depends on perceived cultural norms of religion (i.e., whether it is considered normal and desirable to be religious in a given country). In a two-stage procedure, the teams first created an analysis plan and then executed their planned analysis on the data. For the first research question, all but 3 teams reported positive effect sizes with credible/confidence intervals excluding zero (median reported ÎČ=0.120). For the second research question, this was the case for 65% of the teams (median reported ÎČ=0.039). While most teams applied (multilevel) linear regression models, there was considerable variability in the choice of items used to construct the independent variables, the dependent variable, and the included covariates

    Practical tools and strategies for researchers to increase replicability

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    A growing body of evidence indicates that the effects reported in many scientific fields may be overestimated or even false. This problem has gained a lot of attention in the field of psychology, where researchers have even started to speak of a ‘replication crisis’. Fortunately, a number of measures to rectify this problem have already been proposed and implemented, some inspired by practices in other scientific fields. In this review, I briefly examine this issue in the field of psychology and suggest some practical tools and strategies that researchers can implement to increase replicability and the overall quality of their scientific research

    Citation Patterns Following a Strongly Contradictory Replication Result: Four Case Studies From Psychology

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    Replication studies that contradict prior findings may facilitate scientific self-correction by triggering a reappraisal of the original studies; however, the research community’s response to replication results has not been studied systematically. One approach for gauging responses to replication results is to examine how they affect citations to original studies. In this study, we explored postreplication citation patterns in the context of four prominent multilaboratory replication attempts published in the field of psychology that strongly contradicted and outweighed prior findings. Generally, we observed a small postreplication decline in the number of favorable citations and a small increase in unfavorable citations. This indicates only modest corrective effects and implies considerable perpetuation of belief in the original findings. Replication results that strongly contradict an original finding do not necessarily nullify its credibility; however, one might at least expect the replication results to be acknowledged and explicitly debated in subsequent literature. By contrast, we found substantial citation bias: The majority of articles citing the original studies neglected to cite relevant replication results. Of those articles that did cite the replication but continued to cite the original study favorably, approximately half offered an explicit defense of the original study. Our findings suggest that even replication results that strongly contradict original findings do not necessarily prompt a corrective response from the research community. </jats:p
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