The DCI index: Discounted cumulated impact-based research evaluation

Research evaluation is increasingly popular and important among research funding bodies and science policy makers. Various indicators have been proposed to evaluate the standing of individual scientists, institutions, journals, or countries. A simple and popular one among the indicators is the h-index, the Hirsch index (Hirsch 2005), which is an indicator for lifetime achievement of a scholar. Several other indicators have been proposed to complement or balance the h-index. However, these indicators have no conception of aging. The AR-index (Jin & al. 2007) incorporates aging but divides the received citation counts by the raw age of the publication. Consequently, the decay of a publication is very steep and insensitive to disciplinary differences. In addition, we believe that a publication becomes outdated only when it is no more cited, not because of its age. Finally, all indicators treat citations as equally material when one might reasonably think, that a citation from a heavily cited publication Järvelin – Persson DFC 2 should weigh more than a citation from a non-cited or little-cited publication. We propose a new indicator, the DCI-index (for Discounted Cumulated Impact), which devalues old citations in a smooth way. It rewards an author for receiving new citations even if the publication is old. Further, it allows weighting of the citations by the citation weight of the citing publication. DCI can be used to calculate research performance on the basis of the hcore of a scholar or any other publication data set. Finally, it supports comparing research performance to the average performance in the domain and across domains as well.