Figure 1.

Map of interaction activities with stakeholders for the development and validation of the systems diagram. The numbers 1a,b,c to 7 a,b,c refer to the stakeholder engagement activities listed in Table 1, e.g., 1a is a stakeholder interview with Médecins sans Frontières in Brussels. The concentric rings, with the resulting IMS diagram in the centre, indicate the system levels at which the stakeholder operates, or has his or her expertise. The four outer orientations (Vaccine supply, Humanitarian operations, Immunisation demand and Healthcare system) refer to the main background of the stakeholders. One activity can appear at different locations, for example, a group model building session with stakeholders with different backgrounds. The grey arrows show the iterative, multi-level knowledge build-up while the black arrows indicate how this knowledge flows to and from the IMS diagram under construction.