c-index and Subindices of the h-index: New Variants of the h-index to Account for Variations in Author Contribution

Abstract

ObjectivesBibliometrics are used to assess or compare the academic productivity of individuals or groups. Most of these metrics, including the widely used h-index, do not recognize the added contribution that is generally provided by authors listed first, second, second-to-last and last (enhanced positions) in a publication citation. We propose the c-index as a novel modification to the h-index that will better reflect an individual’s academic output, incorporating authorship position.MethodsOne hundred and sixty-six academic neurosurgeons in eight New York City (NYC) metropolitan region training programs were identified through department websites. Using the Scopus citation database, bibliometric profiles were created for each surgeon. Once an individual’s h-index was calculated, the h-core articles (those with h or more citations) were specifically assessed to determine citation author position. Novel bibliometric indices were created to reflect the number of h-core articles that accounted for primary (hp), senior (hs) or internal authorship (hi) position. Weighted “involvement factors” for primary (ip) and senior (is) author contribution were created to reflect the added value of “enhanced position” authorship in an individual’s h-core publications. c-indices were created to reflect the author’s h-index once augmented by primary (cp), senior (cs), and overall (co) “enhanced position” authorship. Comparisons were made within each institution and across institutions, according to academic rank (assistant professor, associate professor, professor and chairperson).ResultsBreakdown by academic rank showed an increasing average h-index progressing from assistant professor through professor rank with no significant difference demonstrated between professor and chair status. This pattern was seen across all departments (aggregate) but with fewer instances of significance at the level of individual departments. After h-index modification, cp, cs, and co indices showed a similarly significant trend. As faculty rank increased, there was a significant trend toward increasing numbers of articles with authors in enhanced positions and a higher percentage of articles with the author in a senior position. Academic faculty had higher h, cp, and cs indices than clinical faculty. Evaluation of each individual department revealed no significant trend regarding a department’s higher average cp or cs. Average c-index for a department paralleled the average h-index of that department, with larger departments tending to have larger cumulative h, cp, cs, and co indices. No consistent correlation was seen between mean h-indices and academic rank at an individual departmental level.ConclusionsThis study examines the academic productivity of a subset of neurosurgical programs in the NYC metropolitan area as a test bed for novel bibliometric indices. hp, hi, and hs represent the respective number of primary, internal and senior authorship papers that comprise an individual’s h-core papers. cp, cs, and co, variations of the h-index metric,...

Over-optimization of academic publishing metrics: observing Goodhart’s Law in action

“…Certainly, newer academic publishing metrics have emerged that are less biased [20, 24–27], and these may thwart the trend of measures becoming targets. Yet, the traditional metrics retain a strong hold on the overall academic system, and they are still widely used for ranking purposes [28, 29].…”

“…For example, “the h-index does not work well in the field of life sciences, where an author’s position on a paper typically depends on the author’s contribution” [25]. To tackle this issue, various measures such as the c-index [24] and revised h-index [25] have been suggested. These measures give higher weights to authors according to the co-author order.…”

“…Even with their many known shortcomings [8, 24, 55, 68–70], measures such as the impact factor, citation number, and h-index are still widely used. For example, the Journal Citation Reports publishes annual rankings based on journals’ impact factors, and it continues to be widely followed [29].…”

The most highly-cited authors who published papers on the topic of health behavior: A Bibliometric Analysis

“…Although the h-index can measure both the productivity and citation impact of the publications of a scientist, one of its shortcomings is the assumption of equal credits for all coauthors in an article. [4,5] Many studies [6][7][8] have been conducted to investigate individual researchers achievements (IRA) in a specific discipline. However, all or which ignored the co-author contributions unequal in an article byline.…”

“…However, all or which ignored the co-author contributions unequal in an article byline. [5][6][7][8][9] Although many authors developed schemes for quantifying author contributions in the literature, [10][11][12][13][14][15][16] none had been successfully used so far in academics. A general authorship-weighted scheme (AWS) is thus required to develop for use in the empirical discipline.…”