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

The difficulty in evaluating the research performance of groups is attributable to the following two factors: 1) difference of population size or discipline of group members and 2) skewed distribution of the research performance of individuals. This study attempts to overcome this difficulty, focusing on the research performance based on publication productivity. We employ the normalized index for the number of papers, in which publication efficiency was considered and disciplinary variation in the publication intensity was corrected by the disciplinary averages, to calculate a new percentile rank score. The score was developed on the basis of the principle that a person who is rare is valuable. The score was also tested with publication data for faculty members of 17 Japanese universities. The employment of the normalized index increased the score of universities with relatively few faculty members working in the disciplines of high productivity, resulting in more plausible university rankings. The rankings show a high correlation with those for a previously established percentile rank score, which was developed for citation analysis, and they are consistent with the judgment by evaluators of several universities under study. The advantage of the new score over the previous one is that it has no room for arbitrariness in determining the scheme of rank classification and the weights given to each rank class.