Journal analyses can be used for faculty and institution-level evaluation and for collection building and maintenance within the library—that is, for promotion and tenure situations, to rank journals, for decision-making in cancellation projects, for the solicitation of research funds, and for many other things purposes.
Most bibliometrics are citation-based. The premise behind citation analysis is that the more times an author or a journal appears in citations, the more influential and important these are for any given field. Until recently, the ISI Thomson Reuters products were the only tools for this type of analysis. That is no longer the case.
There are now many choices among citation-based bibliometrics, which is good because no one tool captures the complete citation universe and all have weaknesses.
Typical weaknesses of citation analysis tools include:
Because each tool will produce different results, it is highly recommended that multiple approaches by used in determining citation counts per author, the importance of individual journals to a given field, and other measurements.
As stated by the International Mathematical Union's committee on quantitative assessment of research: "The sole reliance on citation data provides at best an incomplete and often shallow understanding of research—an understanding that is valid only when reinforced by other judgments."