Betweenness centrality – a metric of a node in a network that measures how likely an arbitrary shortest path
in the network will go through the node.
Burst terms – single or multi-word phrases extracted from the title, abstract, or other fields of a bibliographic
record and the frequency of the term bursts, i.e. sharply increases, over a period of time.
Citation – an instance that a publication references to another publication.
Citation half-life – the number of years that a publication receives half of its citations since its publication.
Citation tree-rings – outwards growing rings of a node to depict its time series of citations. The thickness of a
ring is proportional to the citations in the corresponding year.
Cluster view – a network is visualized in a modified spring-embedder node placement algorithm.
Co-authors – authors who appear in the author field of the same bibliographic record.
Co-citation – an instance in which two items, such as authors, documents, or journals, that are cited by a
publication.
Color map – a spectrum of colors used by CiteSpace to depict temporal order of observations.
EM clustering – Expectation Maximization (EM) clustering nodes based on various attributes such as citations,
citation half-life, and betweenness centrality. The use of temporal attributes can help the visualization of
emerging trends.
MeSH terms – Medical Subject Heading terms are a set of controlled vocabulary compiled by the National
Library of Medicine. CiteSpace shows MeSH terms assigned to nodes if there are matches in PubMed.
Pathfinder network scaling – a network scaling algorithm that removes links that violate triangle inequality
conditions so as to simplify a network by retaining salient links and paths only.
Pivotal points – see Turning points.
Publication types – study design types extracted from PubMed for clinical trial studies, including meta-
analysis and randomized clinical trials.
Spotlight – visualized networks rendered by fading out links that are not connecting pivotal points.
Thresholds – selection criteria used by CiteSpace – items must have measures above threshold values to be
included in modeling and visualization processes.
Time slicing – a divide-and-conquer strategy that divides a period of time into a series of smaller windows.
Time-zone view – a restricted view in which the movement of nodes is limited to vertical time zones
corresponding to the time of their publication.
Turning points – nodes of high betweenness centralities (> 1.00). Such nodes tend to be critical in network
transitions from one time slice to another.
