Estimates of the Continuously Publishing Core in the Scientific Workforce

Background The ability of a scientist to maintain a continuous stream of publication may be important, because research requires continuity of effort. However, there is no data on what proportion of scientists manages to publish each and every year over long periods of time. Methodology/Principal Findings Using the entire Scopus database, we estimated that there are 15,153,100 publishing scientists (distinct author identifiers) in the period 1996–2011. However, only 150,608 (<1%) of them have published something in each and every year in this 16-year period (uninterrupted, continuous presence [UCP] in the literature). This small core of scientists with UCP are far more cited than others, and they account for 41.7% of all papers in the same period and 87.1% of all papers with >1000 citations in the same period. Skipping even a single year substantially affected the average citation impact. We also studied the birth and death dynamics of membership in this influential UCP core, by imputing and estimating UCP-births and UCP-deaths. We estimated that 16,877 scientists would qualify for UCP-birth in 1997 (no publication in 1996, UCP in 1997–2012) and 9,673 scientists had their UCP-death in 2010. The relative representation of authors with UCP was enriched in Medical Research, in the academic sector and in Europe/North America, while the relative representation of authors without UCP was enriched in the Social Sciences and Humanities, in industry, and in other continents. Conclusions The proportion of the scientific workforce that maintains a continuous uninterrupted stream of publications each and every year over many years is very limited, but it accounts for the lion’s share of researchers with high citation impact. This finding may have implications for the structure, stability and vulnerability of the scientific workforce.背景 科学家保持持续发表学术成果的能力或至关重要，因科研工作需保持持续投入。然而目前尚无数据可统计，长期内每年均能发表成果的科学家占比几何。 方法与主要发现 本研究依托完整的斯科普斯数据库（Scopus），估算得到1996年至2011年间共有15153100名具备正式发表记录的科学家（以独立作者标识符计）。但其中仅有150608人（占比不足1%）在这16年周期内每年均有学术成果发表，即实现了文献发表的不间断持续参与（uninterrupted continuous presence，下文简称UCP）。这类规模极小的UCP核心群体的被引频次远高于其他研究者，其贡献占同期全部学术论文的41.7%，以及同期被引量超过1000的论文总量的87.1%。哪怕仅跳过1年发表，也会对研究者的平均引用影响力产生显著负面影响。此外，本研究通过推演与估算UCP的诞生与消亡事件，分析了这一高影响力UCP核心群体的成员更迭动态：据估算，1997年共有16877名科学家符合UCP诞生标准（1996年无发表记录，1997年至2012年实现UCP），另有9673名科学家在2010年迎来UCP消亡。UCP作者的相对占比在医学研究领域、学术机构以及欧美地区更为集中；而无UCP的作者则更多分布于社会科学与人文科学领域、工业界以及其他大洲。 结论 能够在多年间实现每年不间断持续发表学术成果的科研工作者占比极低，但这类群体却占据了高引用影响力研究者的绝大多数。这一发现或对科研队伍的结构、稳定性与脆弱性产生重要启示。