Advanced and Delayed Information in Requirements Engineering

Background

The Requirements Engineering process has several activities which involve elicitation of knowledge and creation of one or more models to record it. Eliciting and modeling software requirements or related information are two highly related activities (Zowghi & Coulin, 2005; Hull, Jackson & Dick, 2005). They may be coupled in several ways, being canonicals: “model driven elicitation” and “elicitation driven modeling.” In the former, the requirements engineer tries to capture only the information that he or she needs for the model under construction. In the latter, the requirements engineer creates all models at the same time recording every piece of information gathered in the model to which it belongs. Each of these approaches has advantages and drawbacks.

If the information is elicited for a given model, the requirements engineer pays attention only to some part of what he or she is watching, reading or listening to. Then, he or she will discard any information which is not focus-oriented. When the requirements engineer starts the creation of another model, he or she will change the focus and perhaps will now pay attention to information previously disregarded, provided that he or she comes across with the same information. Unfortunately, this does not always happen, especially when the source of information is people. In other words, model driven elicitation tends to make completeness difficult.

If all information obtained is registered at the same time, every model of the process is “opened” at the same time, and also, none is finished during an important period. Lack of coherence among models, poor understanding of the information gathered and misplaced information are the main drawbacks of this approach. However, the loss of information is reduced.