Table 1.

Network analysis glossary

Term	Definition
Ego	The focal hospital unit; this is the unit whose behavior is being analyzed.
Alter	A hospital unit connected to the ego; this is the unit which is potentially influencing the behavior of the ego.
Node	An object that may or may not be connected to other objects in a network; for our application, nodes in the network represent hospital units.
Tie	A connection between 2 nodes that can be either 1 way or 2 way based on the direction (or lack thereof) of movement between 2 nodes; for our application, a tie represents infusion pump movement between 2 hospital units.
Cluster	A subset of nodes in a network that are densely connected to each other and sparsely connected to other nodes in the network; for our application, a cluster represents a subset of hospital units that share infusion pumps more often with each other than with other units in the hospital.
Degree of separation	The operational distance between 2 hospital units as measured by the smallest number of intermediary ties between an ego unit and other nodes within the network. For a given ego, alters are degree 1, as they are directly connected to the ego. Nodes that are connected to the alters but not to the ego are degree 2, and so on. This is also known as the “geodesic distance.”