A Normalized Index to Quantify Publication Productivity across Disciplinary Boundaries

Abstract

The number of papers and number of citations have been widely used as indices for research capability in various situations, such as the comparison of research institutions and performance evaluation of researchers. However, it is well known that these naïve indices have large disciplinary variations, making them difficult to apply across disciplinary boundaries. Although various normalized citation indices have been provided by research assessment tools, no widely accepted indices have been established for the number of papers despite this number's significance in research performance metrics. In the present paper, we propose a normalized index for the number of papers to enable a fair comparison of research capability. A key idea is to introduce the concept of work efficiency into the quantification of publication productivity. We further investigate the effects of normalization on the publication data of our institute. The normalization resulted in a relative change in the total number of papers in inverse relation to publication intensity in each discipline. Similar results were obtained between two major bibliometric databases for the publication productivity in well-populated disciplines with similar field coverage. Bootstrap analysis revealed that a sample size of 200-300 is required to obtain statistically significant publication productivity.

Visualizing University Departments’ Research Achievements, Including in the Humanities and Social Sciences: A Non-Bibliometric Index Approach

“…The number of outputs such as papers tends to be lower in the humanities and social sciences than in science and engineering, but since there are differences among the disciplines, an index has been developed to compensate for this (a normalized index to quantify publication productivity) [5].…”

A percentile rank score of group productivity: an evaluation of publication productivity for researchers from various fields

“…The publication data used in the present study were collected from Scopus at the individual level, based on a list of researchers in 2019, for 9 years from 2010 to 2018 inclusive. The long time window was chosen to ensure the sufficient sample size required for accurate determination of the DWPP following Yamamoto and Ishikawa (2017). It also enables us to minimize the effect of non-publishing authors within a given period, the so-called "potential authors" (e.g., Schubert and Telcs, 1986;Koski et al, 2016) because it would be reasonable to assume that those who do not publish over such long periods are unlikely to publish after the defined period, which means they are not counted as the potential authors to be included in the analysis.…”

“…The following is an overview of the DWPP proposed by Yamamoto and Ishikawa (2017). To take the work efficiency into consideration, a unit of publication effort is defined as manpower, with each researcher having a total of one manpower in a given time period.…”

“…This study employs the normalized index for the number of papers named as Discipline Weighted Publication Productivity (DWPP) proposed by Yamamoto and Ishikawa (2017) to make a group comparison across population sizes and disciplines of its constituent members. The DWPP is calculated at the individual level as a ratio of paper count as an output to publication effort as an input to represent publication efficiency; the publication effort is here defined as an individual's effort devoted to a research field following Schubert et al (1988).…”