A Normalized Index to Quantify Publication Productivity across Disciplinary Boundaries

Abstract

The number ofpapers and number ofcitations 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 na¨ıve 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.