Altmetrics are data that can explain both the volume and nature of attention that research receives online. Certain kinds of altmetrics are also indicators for potential downstream impact.
Altmetrics are complementary to citation-based metrics (citation counts, Journal Impact Factor, and so on), and distinct from social media metrics (which don’t measure the attention paid specifically to research online; instead they measure the overall reach of and engagement with social media accounts) and usage statistics (which showcase only the volume of attention research has received). High-quality altmetrics make the underlying source data available (i.e. who is saying what about research) as a measure to ensure against gaming and provide context for the numbers using disciplinary and time-based percentiles.
Altmetrics can directly measure attention
Altmetrics can measure how many people have shared or engaged with a scholarly output (e.g., an article, a book, a dataset, software, posters, presentations, videos, and virtually anything else). Examples of this include mentions on Twitter or in the mainstream media; page views and downloads; GitHub repository watchers.
Altmetrics can sometimes indicate potential impact
Some types of altmetrics data can signal that research is changing a field of study, the public’s health, or having any other number of tangible effects upon larger society. Examples of this include references in public policy documents; or commentary from experts and practitioners. To get at true evidence of impact, you need to dig deeper into the numbers and look at the qualitative data underneath: who’s saying what about research, where in the world research is being cited, reused, read, etc, and so on.