How difficult is it for an early career academic to climb the ranks of their discipline? We tackle this question with a comprehensive bibliometric analysis of 57 disciplines, examining the publications of more than 5 million authors whose careers started between 1986 and 2008. We calibrate a simple random walk model over historical data of ranking mobility, which we use to (1) identify which strata of academic impact rankings are the most/least mobile and (2) study the temporal evolution of mobility. By focusing our analysis on cohorts of authors starting their careers in the same year, we find that ranking mobility is remarkably low for the top and bottom-ranked authors, and that this excess of stability persists throughout the entire period of our analysis. We further observe that mobility of impact rankings has increased over time, and that such rise has been accompanied by a decline of impact inequality, which is consistent with the negative correlation that we observe between such two quantities. These findings provide clarity on the opportunities of new scholars entering the academic community, with implications for academic policymaking.

翻译：早期学术研究者在其学科领域中攀登排名有多困难？我们通过对57个学科的综合文献计量分析来探讨这一问题，研究对象为1986年至2008年间开始职业生涯的超过500万名作者发表的论文。我们基于排名流动性的历史数据校准了一个简单的随机游走模型，该模型用于：（1）识别学术影响力排名中最具/最不具流动性的层级；（2）研究流动性的时间演变。通过聚焦同年开始职业生涯的作者群体进行分析，我们发现排名靠前和靠后的学者流动性极低，且这种过度稳定性在我们的整个分析期间持续存在。我们还观察到，影响力排名的流动性随时间推移而增强，而这一增长伴随着影响力不平等的下降，这与我们观察到的两者之间的负相关关系一致。这些发现为进入学术社区的新学者的机会提供了清晰的认识，对学术政策制定具有启示意义。