9.2.2 Evaluation Step 1: Decide on an Analysis Question

In this pre-requisite step for model evaluation, the modeler poses a question which can be answered through the model. Multiple questions could be formulated to explore and compare various “what-if” scenarios. Also, one “what-if” question may involve multiple parts so that the modeler can test the effects of more than one element on more than one element. Typically questions have sources and targets, “If (a set of source elements) are (fully/partially satisfied/denied), what are evaluation values of (set of target elements)?”

Figure 2 in the next section 1.4.6.5.1.4 depicts one model out of a series of relatively simple models that are used to illustrate the evaluation procedure. In this model the PC Product Provider wants to Sell PC Products for Profit. In order to do this it needs to Produce PC Products and make a Profit. Profit is affected by PC Users Abiding by Licensing Regulations, which the PC Product Provider depends on the PC User to fulfill. It is also affected by having PC Products be Desirable, which is helped by Allowing Peer-to-Peer Technology. The Data Pirate depends on the PC Product provider to Allow Peer-to-peer Technology in order for it to Make Content Available Peer-to-Peer. The PC User wants to Obtain PC Products, and it can do this by Purchasing Products or Obtaining them from the Data Pirate. In the first option Licensing Regulations are Abided by but products are not very Affordable, in the second option Licensing Regulations are broken, but Products are more Affordable.

At this stage, we would like to pose an analysis question and try to use the model to answer this question. “If the PC product Provider (Role) decides to not Allow Peer-to-Peer Technology (Softgoal), what effect will this have on Sell PC Products for Profit (Task)?” The next steps of the evaluation procedure walk through the model to answer this question. Other questions could be also asked. For example, if the PC Product Provider (Role) decides to Allow Peer-to-Peer Technology (Softgoal), what effect will this have on Affordable Pc Product (Softgoal) of the PC User (Role)? Also, if the PC User (Role) decides to Obtain PC Products from Data Pirates (task), what effect will this have on the Profit (Softgoal) of the PC Product Provider (Role)?

The Modeler might answer a question about elements that have simple and noticeable interactions. Generally, an answer to a question tends to be harder when the relationship between the nodes must be traced though the model.






Open Version



For questions regarding i* syntax please click on the "discuss" tab. This feature is available for registered users only. For registration information please see the Registration and User Rights Policy for the i* Wiki.