## Glossary

affiliation network

a specific class of 2-mode network where ties are restricted as only existing between nodes of different classes, e.g., people and events. (see also: two mode network; bipartitite network)

alter

those nodes to whom an ego is connected; generally the linked (i.e., non-focal) nodes in a network research design. (see also: ego)

arc

a directed network tie. (see also: directed networks; antonym: edges)

bipartite network

a 2-mode network that maintains both modes of nodes within the graph for visualization and/or analyses. (see also two mode network)

closure

a general tendency for local network density. (see also, transitivity)

clustering

how structurally segregated a network is; generally summarized with statistics that estimate how segmented a network is into separate groups, where most ties are within (and not across) groups. (see also, transitivity)

complete network design

. a network that enumerates an entire population and all of the relationships among the members of that population. (see also: ego & partial network designs)

complex network

a network involving some combination of multiple dimensions, e.g., multiplex, multiscale (see hypergraph), multi-slice (i.e., temporal variability), or multimode (see two mode). (see also: simple network)

component

a subsection of a graph where all nodes are mutually reachable from each other.

edge

an undirected network tie. (see also: undirected networks; antonym: edges)

ego

the focal node in a network; if a survey-based study, generally equivalent to respondent. (see also: alter)

ego network design

a research strategy for sampling and measurement that captures relationship characteristics around a focal node. (see also: partial & complete network designs)

directed network

a network where the ties involve partners with unique positions in respect to the relationship (e.g., sender and receiver). Directed ties are generally referred to as arcs.

fixed choice

a strategy for identifying network alters that relies on selecting from a pre-populated list of population members. (see also: free listing)

flows

a network tie type emphasizing the actual passage of bits between pairs of nodes in a network.

free listing

a strategy for identifying network alters that provides the respondent with no assistance in identifying potential members of the population. (synonym: open recall; see also: fixed choice)

graph

a term from the mathematical field of graph theory generally referring to any representation (e.g., visualization or matrix) of a network. (synonym: network)

hypergraph

a network where ties can connect any number of nodes simultaneously (i.e., a one-to-many network).

multiplex network

a network that captures multiple relationship types over the same nodeset.

name generator

a prompt to identify which tie between an ego and alter will be elicited; multiple name generators can be used in any study.

name interpreter

a prompt that adds contextual information about measured network ties; generally include node or tie attributes and alter-alter tie estimation.

node

the representation of units (e.g, actors) in a social network. (synonyms: point, vertex)

network theory

considerations of how networks shape outcomes (i.e., network characteristics as independent variables). (see also: theories of networks)

partial network design

a link-tracing sampling design for network research, where a set of seeds are interviewed, then researchers sample some of their named alters; this procedure can repeat for multiple waves. (see also: ego & complete network designs)

pipes

a network metaphor, theoretically emphasizing the potential passage of bits between nodes in the network.

point

the depiction of an actor (or node) in a network visualization. (synonyms: point, node)

prisms

a network metaphor, theoretically emphasizing the different/similar positions within a network.

reachable path

a path of any non-infinite length connecting a pair of nodes in a graph.

reciprocity

a process of dyadic balance. If node i sends a tie to node j, reciprocity suggests an elevated likelihood of also observing a tie from j to i.

simple network

a network including a single representation of one relationship type, over one node type, captured at one point in time. (see also: complex network)

social interactions

a network tie type emphasizing the more ephemeral joint participation in shared activities by pairs of nodes.

social relations

a network tie type emphasizing the durable role relationships connecting pairs of nodes.

ties

the representation of relationships in a social network. (synonyms: edges, arcs).

theories of networks

considerations of what shapes the structure and changes of networks (i.e., network characteristics as dependent variables). (see also: network theory)

transitivity

a process of local network closure/clustering. If nodes j, k share a tie with node i, social network transitivity suggests an elevated likelihood of observing a tie between (j,k).

two mode network

a network involving nodes of two different classes (modes) of nodes. (see also: affiliation network; bipartitie network; generally: multimode)

undirected network

a network where the ties involve partners with undifferentiated positions in respect to the relationship (e.g., siblings). Undirected ties are generally referred to as edges.

vertex/vertices

a graph theoretic term for the actors in a social network. (synonyms: point, node)