Define Nodes, Ties, and Boundaries Before Analysis
Translate a relational question into an explicit network design by defining who can be a node, what counts as a tie, and where observation begins and ends.
Method sources
By the end of this tutorial
- 1Distinguish a relational question from a question about individual attributes alone.
- 2Write operational definitions for nodes, ties, direction, weight, boundary, and time window.
- 3Separate an observed absence of a tie from missing or unobserved relational data.
SNA
Network specification
Analysis scenario
A course team asks how students seek help while completing a group project. Before calculating a metric, the team must decide whether the network represents advice, friendship, messages, co-membership, or another relationship, because each choice creates a different network.
Nodes
Students officially enrolled in the project course for the full four-week observation window.
Ties
A directed tie from A to B means A reported seeking substantive project advice from B at least once during the window.
Network type
One-mode, directed, binary advice network with loops disallowed and all eligible students retained.
Step-by-step tutorial
Start with a relational question
Write a question whose answer depends on connections, such as who seeks advice from whom or how separate groups exchange knowledge. If the question can be answered from one row per person without relationships, SNA may not be the needed approach.
Checkpoint
The question names a relationship and a structural pattern, not only an individual outcome.
Define the nodes and boundary
State the unit represented by each node and the rule for inclusion. Use roster, event, positional, or another defensible boundary rule, and specify the dates during which actors and ties were eligible to be observed.
Checkpoint
Another analyst could reproduce the node set from the written inclusion rule without asking whom you intended to include.
Operationalize the tie
Describe the event or report that creates a tie, its direction, whether it is binary or weighted, whether loops are possible, and how repeated events are combined. Avoid treating platform proximity as a social relation without justification.
Checkpoint
A raw record can be classified consistently as a tie, a non-tie, or missing under the rule.
Write the network specification
Record the research question, node rule, tie rule, boundary, observation window, direction, weight, loop rule, missing-data rule, and intended analysis. Add one sentence describing what the network cannot observe.
Checkpoint
The specification is complete before visualization or metric selection begins.
Interpret with care
The network is not discovered automatically in raw data. It is constructed through defensible measurement choices. A roster boundary answers a different question from an event-based boundary, and an advice nomination answers a different question from a message count or shared group membership.
Every later measure inherits these choices. Centrality, density, communities, and models cannot repair a vague tie definition or an incomplete boundary. Sensitivity analysis can compare plausible specifications, but the original question and data-generating process must guide which version receives the primary interpretation.