One of the critical steps in modelling an organization either for design or diagnosis is to understand the structure of how the organization deals with the complexity of the tasks it carries out. Primary activities are the tasks that the organization does that deliver value to the external ‘customers’ of the system. The term primary is a statement of the purpose the organization exists to fulfil and the expectations that customers have of the organization. It is not a comment on the importance of tasks. Doing the accounts in the building company may be vitally important to ensuring that the company stays in existence and is able to service its clients, just as maintaining the building may be equally vital to the firm of accountants.