Requirements work is not finished as soon as requirements have been gathered. They must be organized, documented, analyzed, communicated, and managed throughout the project lifecycle. This ongoing requirements work impacts every project large or small. On very small projects these activities may be informal. As projects grow in size or complexity, more is needed to ensure common understanding. Modeling requirements helps with the organization, analysis, and communication activities.
What Types of Requirements Models Exist?
The three most frequent types of analysis each have their own sets of models and modeling techniques (see table below). Projects often combine analysis approaches and will use some cross-section of the modeling techniques. A number of techniques are applicable across the types of analysis.