This paper investigates the stability of Twitter counts of scientific publications over time. For this, we conducted an analysis of the availability statuses of over 2.6 million Twitter mentions received by the 1,154 most tweeted scientific publications recorded by Altmetric.com up to October 2017. Results show that of the Twitter mentions for these highly tweeted publications, about 14.3% have become unavailable by April 2019. Deletion of tweets by users is the main reason for unavailability, followed by suspension and protection of Twitter user accounts. This study proposes two measures for describing the Twitter dissemination structures of publications: Degree of Originality (i.e., the proportion of original tweets received by a paper) and Degree of Concentration (i.e., the degree to which retweets concentrate on a single original tweet). Twitter metrics of publications with relatively low Degree of Originality and relatively high Degree of Concentration are observed to be at greater risk of becoming unstable due to the potential disappearance of their Twitter mentions. In light of these results, we emphasize the importance of paying attention to the potential risk of unstable Twitter counts, and the significance of identifying the different Twitter dissemination structures when studying the Twitter metrics of scientific publications.

中文翻译：

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Twitter 指标的稳定性：一项关于不可用 Twitter 提及科学出版物的研究

本文调查了科学出版物 Twitter 计数随时间的稳定性。为此，我们对 Altmetric.com 截至 2017 年 10 月记录的 1,154 篇推文最多的科学出版物收到的超过 260 万次 Twitter 提及的可用性状态进行了分析。结果显示，这些推文最多的出版物在 Twitter 上的提及中，大约有 14.3 % 已在 2019 年 4 月变得不可用。用户删除推文是不可用的主要原因，其次是暂停和保护 Twitter 用户帐户。本研究提出了两种描述出版物在 Twitter 上的传播结构的衡量标准：原创度（即论文收到的原始推文所占的比例）和集中度（即转推集中在单个原始推文上的程度）。具有相对较低的原创度和相对较高的集中度的出版物的 Twitter 指标被观察到由于其 Twitter 提及的潜在消失而变得不稳定的风险更大。鉴于这些结果，我们强调了关注 Twitter 计数不稳定的潜在风险的重要性，以及在研究科学出版物的 Twitter 指标时确定不同的 Twitter 传播结构的重要性。