Scholarly metrics are used for faculty and institution-level evaluation, most commonly in promotion and tenure situations, but also for many other reasons: for the solicitation of research funds, for library collection management, for identifying a publication in which to submit work, and more. Most scholarly metrics, commonly called bibliometrics, are citation-based. When used as an assessment tool for evaluating authorial output or ranking journals, the premise behind citation analysis is that the more times an author or journal appears in citations, the more influential and important the work is in a given field.
Until recently, there existed only a handful of citation-based tools. That is no longer the case. In addition, there are growing options in the development of non-citation-based scholarly metrics. The tools in this movement are popularly known as "Altmetrics" or (somewhat confusingly) "Article-Level Metrics - ALMs." The latter is confusing, because while ALMs encourage use of article-level citation analysis, they are not restricted to article-level metrics. Indeed, ALMs include social and other media measurements. For the purposes of this guide, Altmetrics and ALMs are separated from other article-level citation analysis tools.
The assumptions and application of Scholarly Metrics are controversial.