Scientometric indicators have been classified by various researchers into different categories. These categories are based on a defined set of the characteristics of indicators. Though the foundation of scientometric indicators have a history dating back to the advent of Science Citation Index (SCI) database by Eugene Garfield in Philadelphia in 1963. Researchers from different fields have described how these indicators can be categorized depending upon the facets of their use, application, subject area etc. Various studies regarding the classification and categorization of scientometric indicators have been put forth at various levels. The most prominent amongst them are discussed in this chapter.
Okubo (1997) categorized Scientometric indicators in two classes.
The first class is dedicated to the quantitative indicators, which reflect the quantitative aspect of science and technology activities. Quantitative indicators of Science and Technology comprises of the number of papers, the number of co-signers, the number of citations, the number of patents and the number of patent signer citations.
The second deals with relational indicators, i.e. indicators that quantify relations and collaborations among the various performers in S&T systems, particularly in the international perspective. Relational indicators include Co-citations, Co-publications, the affinity index, Correlations between scientific papers and patents, scientific links measured by citations, and the “co-occurrence” of words.
Likewise Gauthier (1998) classified scientometric indicators into following two major categories: