"As people interact with research they leave online “footprints.” Plum Analytics gathers these footprints and creates and categorizes metrics on individual pieces of research output (articles, conference proceedings, book chapters, and many more). These metrics are collectively known as PlumX Metrics."1
1. How are Article Metrics used in Scopus? - Scopus: Access and use Support Center. https://service.elsevier.com/app/answers/detail/a_id/12031/supporthub/scopus/kw/plumx/. Accessed February 7, 2020.
2. Metrics - How Scopus Works - Scopus - Solutions | Elsevier. https://www.elsevier.com/solutions/scopus/how-scopus-works/metrics. Accessed February 7, 2020.