Table 3.

Description of co-citation clusters.^a

Mean yearb	Cluster ID	Sizec	Silhouette	Label (LLRd)
2003	15	10	0.984	User groups perspective
2005	3	69	0.805	Clinical decision support
2005	5	62	0.815	Information technology diffusion
2005	10	31	0.777	Clinical documentation
2006	1	72	0.872	Integrative review
2006	13	18	0.947	Medication reconciliation issue
2007	4	64	0.838	Quality requirement
2007	6	61	0.809	Contingency factor
2010	2	70	0.804	EHRe systems
2010	7	61	0.847	Clinical decision support system
2010	12	30	0.833	Electronic health information exchange
2011	0	95	0.849	Genomic era
2011	11	31	0.936	Frequency
2013	8	51	0.893	Developing knowledge resource
2013	9	43	0.950	Allocating scarce resource

^aThe connected components in cluster 14 are less than the default value (K=25), so CiteSpace did not report 14 [39].

^bThe average year of the articles in a cluster.

^cThe number of articles in each cluster.

^dLLR: log-likelihood ratio.

^eEHR: electronic health record.