Network analysis glossary
What is a sociogram?
A sociogram is a diagram of the relationships inside a group. Each person is a point and each relationship is a line, so the drawing shows at a glance who is popular, who is left out, which small groups stick together, and who connects them. The psychiatrist Jacob Moreno introduced it in 1934.
Updated · Netgraf
Where the sociogram comes from
Jacob L. Moreno drew the first sociograms in the early 1930s, most famously for a girls' reform school in Hudson, New York, and published them in Who Shall Survive? in 1934. He asked each girl whom she would like to live with, drew an arrow for every choice, and used the picture to regroup the cottages. The method became known as sociometry, and the diagram outlived it: every social network analysis chart is a descendant of Moreno's arrows.
What a sociogram shows
A few shapes recur in almost every sociogram, and each has a name:
- Stars: people chosen by many others. In network terms they have high degree centrality.
- Isolates: people nobody chose and who chose nobody, or whose choices were not returned.
- Cliques: small groups whose members all choose each other. The clustering coefficient measures how common they are.
- Bridges: people who link two groups that would otherwise not touch. Betweenness centrality finds them.
- Mutual pairs: two people who chose each other, drawn as a line with arrows at both ends.
How to make a sociogram
- Decide the question. "Who would you like to sit with?" and "Who do you go to for help?" draw different networks from the same group.
- Collect the answers: usually two or three named choices per person, kept confidential.
- Draw one point per person and one line per choice. Use an arrow when a choice is one way.
- Look for stars, isolates, cliques and bridges, then check the picture against the measures.
In Netgraf you can type the choices in as a two-column spreadsheet (chooser, chosen) and import it, or draw them by hand. Switch the map to the Graph view to see it as a classic sociogram of dots and lines, and open Insights to have the stars, groups and isolates found for you. The classroom sociogram guide walks through it step by step.
Sociogram, social network, relationship map
The three words overlap. A sociogram is traditionally built from a survey of one group's choices. A social network diagram is the general term for any people-and-ties graph. A relationship map usually means a hand-drawn diagram of known ties, such as the owners behind a set of companies or the cast of a show. The drawing and the maths are the same for all three.