Jason P commented to my May 8th entry that a model is not a requirement. I disagree. One of the changes that I would like to see in our industry is a broader use of the word requirement. A requirement can be represented as a sentence, or a symbol on a diagram, or both. For example: Jason says that requirements are derived from models. If I build a data model using an entity relationship diagram, I would not translate those "needs" (requirements) into a textual description (unless the business stakeholders demanded it). The fact that the business needs are represented in a diagram rather than a sentence does not make them any less needed.
I think that it is limiting for us to only use the requirement when we are talking about an English sentence that starts with the words "The system shall . . . ". I would like every artifact that we document to communicate a business stakeholers needs/requests/wishes to be considered a requirement.
February 10th, 2007 at 5:54 pm
I agree with you that a model can be a requirement with one caveat - requirement attributes typically are not defined in models. Requirement attributes are needed to formally describe the requirement (e.g, priority, source, ID, measurement, etc.). A good example is the use case model. Many analysts define use case diagrams and descriptions as their definitive requirements. However, attributes are needed to complete the picture to formally state the requirement. With the above said, there is something that the model does provide that declarative statements don't - context. This is well illustrated by use case because it tells a story that can be used for testing scenarios, training manuals, and system documentation. Recently ESPN broadcasted a show on how NFL films began as a business. Steve Sable of NFL films wrapped up the show with a very profound saying, "Tell me a fact, and I'll remember. Tell me the truth, and I'll believe. But tell me a story, and it will live in my heart forever." Models tell stories………….. The bottom line is that both the model and a formal requirements list with attributes are needed to complete the picture.
June 14th, 2007 at 3:42 am
Bravo