Self-citations are a key topic in evaluative bibliometrics because they can artificially inflate citation-related performance indicators. Recently, self-citations defined at the largest scale, i.e., country self-citations, have started to attract the attention of researchers and policymakers. According to a recent research, in fact, the anomalous trends in the country self-citation rates of some countries, such as Italy, have been induced by the distorting effect of citation metrics-centered science policies. In the present study, we investigate the trends of country self-citations in 50 countries over the world in the period 1996-2019 using Scopus data. Results show that for most countries country self-citations have decreased over time. 12 countries (Colombia, Egypt, Indonesia, Iran, Italy, Malaysia, Pakistan, Romania, Russian Federation, Saudi Arabia, Thailand, and Ukraine), however, exhibit different behavior, with anomalous trends of self-citations. We argue that these anomalies should be attributed to the aggressive science policies adopted by these countries in recent years, which are all characterized by direct or indirect incentives for citations. Our analysis confirms that when bibliometric indicators are integrated into systems of incentives, they are capable of affecting rapidly and visibly the citation behavior of entire countries.

翻译：自引是评估文献计量学中的关键议题，因其可能人为抬高与引用相关的绩效指标。近年来，最大尺度定义的自引（即国家自引）已开始引起研究人员和政策制定者的关注。事实上，近期研究显示，意大利等部分国家自引率的异常趋势，是由以引用指标为中心的科学政策产生的扭曲效应所致。本研究利用Scopus数据，调查了1996-2019年间全球50个国家的自引趋势。结果表明，大多数国家的自引率随时间推移呈现下降趋势。然而，12个国家（哥伦比亚、埃及、印度尼西亚、伊朗、意大利、马来西亚、巴基斯坦、罗马尼亚、俄罗斯联邦、沙特阿拉伯、泰国和乌克兰）表现出不同行为，其自引趋势异常。我们认为，这些异常应归因于这些国家近年来采取的激进科学政策，其共同特征是对引用给予直接或间接激励。我们的分析证实，当文献计量指标被纳入激励体系时，能迅速且显著地影响整个国家的引用行为。