Department of Bioinformatics and 2nd Dept. of Pediatrics, Semmelweis University, Budapest, Hungary.
TTK Lendület Cancer Biomarker Research Group, Institute of Enzymology, Budapest, Hungary.
PLoS One. 2022 Jul 27;17(7):e0271218. doi: 10.1371/journal.pone.0271218. eCollection 2022.
PhD is the highest awarded degree offered by universities in different disciplines. Owners of a PhD can teach at universities, start independent research and receive a higher salary while further building a scientific career. We examined whether the publication output before the PhD degree has a correlation with subsequent research activities.
We downloaded publication and citation data from the Hungarian Scientific Bibliography for Hungarian researchers who obtained PhD between the ages of 24 and 45. The researchers were grouped into eleven scientific sections. We examined the number of Q1 publications published in the previous 5 years, the H-index, the total number of citations for the last complete year, and the biological age of the researcher. Each parameter was computed for the year at which the PhD was obtained and ten years later. Pre-PhD publications (and citations for these) were excluded when assessing post-PhD track records. Spearman rank correlation and Kruskal-Wallis test were computed.
We analyzed all together 4,790 researchers. We obtained a positive correlation between the number of Q1 publications before and after PhD (corr. coeff. = 0.21-0.54, p<0.01 in all sections), between the H-index before and after PhD (corr. coeff. = 0.32-0.56, p<0.01 in all sections), and between the citations received before and after PhD (corr. coeff. = 0.34-0.51, p<0.01 in all sections). All three metrics measured ten years after the PhD were negatively correlated with the age of the researcher at the time of obtaining the PhD (number of publications corr. coeff. = -0.09-0.22, p<0.05; H-index corr. coeff. = -0.09-0.29, p<0.08; number of citations corr. coeff. = -0.14-0.30, p<0.01). Among all disciplines, Philosophy and History and Engineering sciences show the strongest correlation between pre- and post-PhD output. When running multiple regression analysis for all three metrics as dependent variables and the number of articles, the H-index, the number of citations in the year of the PhD, the calendar year of PhD, and the gender of the researcher as independent variables, the number of articles and the H-index in the year of PhD reached the strongest positive correlations while gender had a negative correlation.
We independently evaluated pre- and post-PhD publication performance. In connection with age, the discipline-specific reference values of scientometric parameters at the time of obtaining the PhD can help to select candidates for postdoctoral grants and positions.
博士是不同学科的大学授予的最高学位。拥有博士学位的人可以在大学任教，开展独立研究，并获得更高的薪水，同时进一步发展自己的科研事业。我们研究了博士学位之前的论文发表量是否与后续的研究活动有关。
我们从匈牙利科学书目下载了在 24 岁至 45 岁之间获得博士学位的匈牙利研究人员的论文发表和引用数据。研究人员被分为 11 个科学领域。我们考察了过去 5 年中发表的 Q1 论文数量、H 指数、上一年的总引用次数以及研究人员的生物学年龄。每个参数都是在获得博士学位的那一年和十年后计算的。在评估博士毕业后的记录时，不考虑博士前的论文发表情况（以及这些论文的引用情况）。我们计算了 Spearman 秩相关系数和 Kruskal-Wallis 检验。
我们共分析了 4790 名研究人员。我们发现博士前和博士后的 Q1 论文发表数量之间存在正相关（所有领域的相关系数为 0.21-0.54，p<0.01），博士前和博士后的 H 指数之间存在正相关（所有领域的相关系数为 0.32-0.56，p<0.01），以及博士前和博士后的引用次数之间存在正相关（所有领域的相关系数为 0.34-0.51，p<0.01）。所有三个指标在获得博士学位十年后与研究人员获得博士学位时的年龄呈负相关（发表论文数量相关系数为-0.09-0.22，p<0.05；H 指数相关系数为-0.09-0.29，p<0.08；引用次数相关系数为-0.14-0.30，p<0.01）。在所有学科中，哲学和历史与工程科学之间表现出最强的博士前和博士后产出相关性。当我们将三个指标（作为因变量）分别与发表文章数量、H 指数、博士学位当年的引用次数、博士学位授予年份和研究人员性别作为自变量进行多元回归分析时，博士学位当年的发表文章数量和 H 指数呈现出最强的正相关关系，而性别则呈现出负相关关系。
我们独立评估了博士前和博士后的论文发表表现。结合年龄，在获得博士学位时的科学计量参数的学科特定参考值可以帮助选择博士后奖学金和职位的候选人。
