This diagram is a sociogram, which is a graphical representation of connections between items, in this case, between people attending workshops.
Surveys carried out at the beginning of the workshop and several months after allowed me to construct before and after sociograms showing the nature of relationships.
Specialist software can calculate quantities shown by the sociogram, such as density (how many of the possible connections are in existence?), and closeness (how many people does each individual know?).
This analysis made it possible to develop a quantitative assessment of how relationships changed as a result of meeting at the workshop.