Indicating Studies’ Quality Based on Open Data in Digital Libraries

The phenomenon of self-citation can present in many different forms, including direct, co-author, collaborative, and coercive induced self-citation. It can also pertain to the citation of single scientists, groups of scientists, journals, and institutions. This article presents some case studies of extreme self-citation practices. It also discusses the implications of different types of self-citation. Self-citation is not necessarily inappropriate by default. In fact, usually it is fully appropriate but often it is even necessary. Conversely, inappropriate self-citation practices may be highly misleading and may distort the scientific literature. Coercive induced self-citation is the most difficult to discover. Coercive Induced self-citation may happen directly from reviewers of articles, but also indirectly from reviewers of grants, scientific advisors who steer a research agenda, and leaders of funding agencies who may espouse spending disproportionately large funds in research domains that perpetuate their own self-legacy. Inappropriate self-citation can be only a surrogate marker of what might be much greater distortions of the scientific corpus towards conformity to specific opinions and biases. Inappropriate self-citations eventually affect also impact metrics. Different impact metrics vary in the extent to which they can be gamed through self-citation practices. Citation indices that are more gaming-proof are available and should be more widely used. We need more empirical studies to dissect the impact of different types of inappropriate self-citation and to examine the effectiveness of interventions to limit them.

A randomized, controlled trial (RCT) should not be started or interpreted without accounting for evidence from preceding RCTs addressing the same question. Research has suggested that evidence from prior trials is often not accounted for in reports of subsequent RCTs. To assess the extent to which reports of RCTs cite prior trials studying the same interventions. Meta-analyses published in 2004 that combined 4 or more trials were identified; within each meta-analysis, the extent to which each trial report cited the trials that preceded it by more than 1 year was assessed. The proportion of prior trials that were cited (prior research citation index), the proportion of the total participants from prior trials that were in the cited trials (sample size citation index), and the absolute number of trials cited were calculated. 227 meta-analyses were identified, comprising 1523 trials published from 1963 to 2004. The median prior research citation index was 0.21 (95% CI, 0.18 to 0.24), meaning that less than one quarter of relevant reports were cited. The median sample size citation index (0.24 [CI, 0.21 to 0.27]) was similar, suggesting that larger trials were not selectively cited. Of the 1101 RCTs that had 5 or more prior trials to cite, 254 (23%) cited no prior RCTs and 257 (23%) cited only 1. The median number of prior cited trials was 2, which did not change as the number of citable trials increased. The mean number of preceding trials cited by trials published after 2000 was 2.4, compared with 1.5 for those published before 2000 (P < 0.001). The investigators could not ascertain why prior trials were not cited, and noncited trials may have been taken into account in the trial design and proposal stages. In reports of RCTs published over 4 decades, fewer than 25% of preceding trials were cited, comprising fewer than 25% of the participants enrolled in all relevant prior trials. A median of 2 trials was cited, regardless of the number of prior trials that had been conducted. Research is needed to explore the explanations for and consequences of this phenomenon. Potential implications include ethically unjustifiable trials, wasted resources, incorrect conclusions, and unnecessary risks for trial participants. None.