Web of Science - Impact Factor / citable items
Impact Factors are the #citations/#citable items. Citable items are scholarly items in the journal, primarily research articles and reviews, but also scholarly commentary, essays, and discussion that add to the literature of the subject.
Citable items do not include: editorials, minor editorial correspondence, general news items, small opinion essays, biographical items, interviews, letters, reprints, or minor non-scholarly works as citable items.
Each journal is evaluated individually for the characteristics of the items in each section.