Mapping Science - Mapping Scientific Frontiers: The Quest for Knowledge Visualization - page 294

Fig. 8.12 An overview of co-citation contexts of retracted articles. Each dot is a reference of an
article. Red dots indicate retracted articles. The numbers in front of labels indicate their citation
ranking. Potentially damaging retracted articles are in the middle of an area that otherwise free
from red dots
and overlaid with the top-ten most cited retracted articles as well as other highly
cited articles without retractions (See Fig. 8.12 ). Each dot in the visualization
represents an article cited by the set of 29,756 citing articles. The dots in red
are retracted articles. Lines between dots are co-citation links. The color of a co-
citation link is the earliest time a co-citation between two articles was made. The
earliest time is in blue; more recent time is in yellow and orange. The size of a dot,
or a disc, is proportional to the citation counts of the corresponding cited article.
The top ten most cited retracted articles are labeled in the visualization. Retracted
articles are potentially more damaging if they are located in the middle of a densely
co-cited articles. In contrast, isolated red dots are relatively less damaging. This
type of visualizations will be valuable to highlight how deeply a retracted article is
embedded in the scientific literature.
Figure 8.13 shows a close-up view of the visualization shown in Fig. 8.12 .The
retracted article by Nakao N et al. on the left, for example, has a sizable red disc,
indicating its numerous citations. Its position on a densly connected island of other
articles indicates its relevant to a significant topic. Hwang WS (slightly to the right)
and Potti A at the lower right corner of the image have similar citation context
profiles. More profound impacts are likely to be found in interconnected citation
contexts of multiple retracted articles.
Figure 8.14 shows an extensive representation of the citation context of the
retracted 2003 article by Nakao et al. First, 609 articles that cited the Nakao paper
were identified in the Web of Science. Next, 9,656 articles were retrieved because