A review of the literature on citation impact indicators

Citation impact indicators nowadays play an important role in research evaluation, and consequently these indicators have received a lot of attention in the bibliometric and scientometric literature. This paper provides an in-depth review of the literature on citation impact indicators. First, an overview is given of the literature on bibliographic databases that can be used to calculate citation impact indicators (Web of Science, Scopus, and Google Scholar). Next, selected topics in the literature on citation impact indicators are reviewed in detail. The first topic is the selection of publications and citations to be included in the calculation of citation impact indicators. The second topic is the normalization of citation impact indicators, in particular normalization for field differences. Counting methods for dealing with co-authored publications are the third topic, and citation impact indicators for journals are the last topic. The paper concludes by offering some recommendations for future research

Benchmarking citation measures among the Australian education professoriate

Individual researchers and the organisations for which they work are interested in comparative measures of research performance for a variety of purposes. Such comparisons are facilitated by quantifiable measures that are easily obtained and offer convenience and a sense of objectivity. One popular measure is the Journal Impact Factor based on citation rates but it is a measure intended for journals rather than individuals. Moreover, educational research publications are not well represented in the databases most widely used for calculation of citation measures leading to doubts about the usefulness of such measures in education. Newer measures and data sources offer alternatives that provide wider representation of education research. However, research has shown that citation rates vary according to discipline and valid comparisons depend upon the availability of discipline specific benchmarks. This study sought to provide such benchmarks for Australian educational researchers based on analysis of citation measures obtained for the Australian education professoriate

Revisiting h measured on UK LIS and IR academics

A brief communication appearing in this journal ranked UK LIS and (some) IR academics by their h-index using data derived from Web of Science. In this brief communication, the same academics were re-ranked, using other popular citation databases. It was found that for academics who publish more in computer science forums, their h was significantly different due to highly cited papers missed by Web of Science; consequently their rank changed substantially. The study was widened to a broader set of UK LIS and IR academics where results showed similar statistically significant differences. A variant of h, hmx, was introduced that allowed a ranking of the academics using all citation databases together

How are new citation-based journal indicators adding to the bibliometric toolbox?

The launching of Scopus and Google Scholar, and methodological developments in Social Network Analysis have made many more indicators for evaluating journals available than the traditional Impact Factor, Cited Half-life, and Immediacy Index of the ISI. In this study, these new indicators are compared with one another and with the older ones. Do the various indicators measure new dimensions of the citation networks, or are they highly correlated among them? Are they robust and relatively stable over time? Two main dimensions are distinguished -- size and impact -- which together shape influence. The H-index combines the two dimensions and can also be considered as an indicator of reach (like Indegree). PageRank is mainly an indicator of size, but has important interactions with centrality measures. The Scimago Journal Ranking (SJR) indicator provides an alternative to the Journal Impact Factor, but the computation is less easy