In the data pipeline from the data collection process to the planned statistical analyses, initial data analysis (IDA) typically takes place between the end of the data collection and do not touch the research questions. A systematic process for IDA and clear reporting of the findings would help to understand the potential shortcomings of a dataset, such as missing values, or subgroups with small sample sizes, or shortcomings in the collection process, and to evaluate the impact of these shortcomings on the research results. A clear reporting of findings is also relevant when making datasets available to other researchers. Initial data analyses can provide valuable insights into the suitability of a data set for a future research study. Our aim was to describe the practice of reporting of initial data analyses in observational studies in five highly ranked medical journals with focus on data cleaning, screening, and reporting of findings which led to a potential change in the analysis plan. This review was carried out using systematic search strategies with eligibility criteria for articles to be reviewed. A total of 25 papers about observational studies were selected from five medical journals published in 2018. Each paper was reviewed by two reviewers and IDA statements were further discussed by all authors. The consensus was reported. IDA statements were reported in the methods, results, discussion, and supplement of papers. Ten out of 25 papers (40%) included a statement about data cleaning. Data screening statements were included in all articles, and 18 (72%) indicated the methods used to describe them. Item missingness was reported in 11 papers (44%), unit missingness in 15 papers (60%). Eleven papers (44%) mentioned some changes in the analysis plan. Reported changes referred to missing data treatment, unexpected values, population heterogeneity and aspects related to variable distributions or data properties. Reporting of initial data analyses were sparse, and statements on IDA were located throughout the research articles. There is a lack of systematic reporting of IDA. We conclude the article with recommendations on how to overcome shortcomings in the practice of IDA reporting in observational studies.

中文翻译：

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隐藏分析：审查报告做法和建议，以使初始数据分析的报告更加透明。

在从数据收集过程到计划的统计分析的数据管道中，通常在数据收集结束之间进行初始数据分析（IDA），并且不涉及研究问题。IDA的系统化流程和明确的调查结果报告将有助于了解数据集的潜在缺陷，例如缺失值，样本量较小的亚组或收集过程中的缺陷，并评估这些缺陷对研究结果。使数据集可供其他研究人员使用时，明确报告发现也很重要。初始数据分析可以提供有价值的见解，以了解数据集是否适合将来的研究。我们的目的是描述在五种排名较高的医学期刊中观察性研究报告初始数据分析的实践，重点是数据清洁，筛选和结果报告，这些结果导致分析计划可能发生变化。这项审查是使用系统的搜索策略进行的，该策略具有要审查的文章的资格标准。从2018年出版的五种医学期刊中总共选择了25篇有关观察性研究的论文。每篇论文均由两名审稿人审阅，所有作者进一步讨论了IDA声明。达成共识。在文件的方法，结果，讨论和补充中报告了IDA声明。25篇论文中有10篇（占40％）发表了有关数据清理的声明。数据筛选声明包含在所有文章中，18（72％）表示用于描述它们的方法。11篇论文（44％）报告了项目缺失，15篇论文（60％）报告了单位缺失。11篇论文（44％）提到了分析计划中的一些更改。报告的更改涉及丢失的数据处理，意外的值，总体异质性以及与变量分布或数据属性有关的方面。最初数据分析的报告稀疏，有关IDA的声明遍及整个研究文章。缺乏对IDA的系统报告。我们在文章结尾提出了有关如何克服观察研究中IDA报告实践中的缺点的建议。报告的更改涉及丢失的数据处理，意外的值，总体异质性以及与变量分布或数据属性有关的方面。最初数据分析的报告稀疏，有关IDA的声明遍及整个研究文章。缺乏对IDA的系统报告。我们在文章结尾提出了有关如何克服观察研究中IDA报告实践中的缺点的建议。报告的更改涉及丢失的数据处理，意外的值，总体异质性以及与变量分布或数据属性有关的方面。最初数据分析的报告稀疏，有关IDA的声明遍及整个研究文章。缺乏对IDA的系统报告。我们在文章结尾提出了有关如何克服观察研究中IDA报告实践中的缺点的建议。