Altmetrics

Altmetrics, short for alternative metrics, are indicators that measure the attention and impact of research outputs beyond traditional citation counts.^[1][2] They track engagement across social media platforms, news outlets, policy documents, blogs, Wikipedia references, online reference managers, and download statistics.

Traditional citation based metrics capture only a narrow slice of research impact and can take years to accumulate.^[1] Altmetrics fill this gap by providing near real time indicators of how research is received and used across diverse audiences.^[1] Policy makers, funders, and institutional administrators use altmetrics to evaluate whether research is reaching practitioners, the public, and decision makers.^[2] For individual researchers, altmetrics offer faster feedback on a publication's visibility and can identify unexpected audiences or applications for their work. Altmetrics are particularly valuable for measuring the impact of research that influences policy, public health practice, or public discourse, areas where citation counts may understate the work's true reach.

Altmetric tracking services, most notably Altmetric.com (owned by Digital Science) and PlumX (owned by Elsevier), aggregate data from a wide range of online sources. These include social media platforms such as X (formerly Twitter), Facebook, and Reddit (coverage differs by service: PlumX stopped collecting X data on 31 August 2023, while Altmetric still tracks it); news outlets and science journalism sites; policy documents from organizations like the WHO, NIH, and parliamentary committees; patent filings; Wikipedia articles; blog posts; online reference managers like Mendeley; and download counts from publisher platforms and repositories.

Each data source is weighted differently in composite scores. For example, the Altmetric Attention Score assigns higher weights to policy document citations and news mentions than to social media posts, reflecting the assumption that these sources indicate more substantive engagement. The score is designed to reflect the volume and diversity of attention rather than the quality of the research itself.

Altmetrics are typically displayed alongside traditional metrics on journal article pages, institutional repositories, and research databases such as Scopus (PlumX) and Dimensions (Altmetric). Many publishers now embed altmetric badges (the "donut" visualization) on their article landing pages, allowing readers to see at a glance how much attention a paper has received and from which sources.

It is important to recognize that altmetrics complement rather than replace traditional bibliometrics.^[2] A high altmetric score does not necessarily indicate scientific rigor or quality; a paper may attract extensive media attention because of its topic's novelty or controversy rather than its methodological strength. Conversely, a highly cited paper with a low altmetric score may be deeply influential within a specialized academic community without reaching broader audiences.

Altmetrics are useful when evaluating the broader societal impact of research, when assessing engagement with audiences outside academia, when tracking the dissemination of a newly published paper before citation data become available, and when preparing impact statements for grants or institutional reviews. They are not appropriate as sole indicators of research quality and should always be interpreted alongside peer review assessments and citation based metrics.

A public health paper on the association between air pollution and childhood asthma receives 42 citations in its first two years but accumulates a high Altmetric Attention Score, driven mainly by coverage in 28 news outlets, along with mentions in three WHO policy briefs and over 600 posts on X (formerly Twitter) from public health professionals and patient advocacy groups. The university's research impact office highlights the altmetric data in its annual report to demonstrate the societal relevance of the institution's environmental health program.