Thomas A. Alspaugh

i* is an approach developed by Eric Yu and John Mylopoulos for modelling the organizational context of a software system. Recent work with i* has been done by Neil Maiden and others.

i* diagram key

Figure 1. i* diagram key

i* diagrams

The nodes and edges in i* diagrams appear in Figure 1.

Table 1. Allowed connections (Under Construction)
Source node Edge Destination node
goal, task means-endgoal, soft goal
resource means-endsoft goal
soft goal contribute-to (+ or −)soft goal

Strategic dependency (SD)

A strategic dependency diagram relates actors with needs (“dependers”) to actors with the capability of meeting those needs (“dependees”). The relations are expressed with dependency edges. The needs are expressed in terms of goals. Yu and Mylopoulos use “dependum” to refer to what is needed.

Strategic rationale (SR)

A strategic rationale diagram describes how actors may achieve goals through tasks. Subtasks are linked to their supertasks by task-decomposition edges. Alternative ways of accomplishing a task are linked to the tasks by means-end edges. Subgoals are linked to the goal they help achieve by contribute-to edges.


N. A. M. Maiden, S. Manning, S. Jones, and J. Greenwood. Generating requirements from systems models using patterns: a case study. Requirements Engineering, 10(4):276–288, 2005.
Eric S. K. Yu and John Mylopoulos. From e-r to “a-r” — modelling strategic actor relationships for business process reengineering. In 13th International Conference on the Entity-Relationship Approach (ER ’94), pages 548–565, 1994.
Eric S. K. Yu and John Mylopoulos. Enterprise modelling for business redesign: the i* framework. SIGGROUP Bulletin, 18(1):59–63, 1997.
doi:10.1145/271159.271180 url

The i* wiki.

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