The SBDi Tips have covered a lot of territory. Previous tips introduced the Requirements Set Framework™ and the Requirements Set Pattern™. Unfortunately, there is no such thing as a silver bullet! In other words, defects in the Requirements Set can still occur while using both the Framework and Pattern. This is the case even with the addition of best practices, techniques, and tools. It is for this reason that Requirements Anti-Patterns need to be developed and implemented to avoid common requirement-related traps.

Anti-Patterns were introduced to the world of design by Christopher Alexander. His use of Anti-Patterns began with the planning of towns and the subsequent construction of buildings within these towns. Ward Cunningham and Kent Beck applied Alexander's approach to developing user interfaces in Smalltalk programming language. In 1994, Anti-Patterns were launched into the mainstream when Jim Coplien submitted a paper to the first Pattern Languages of Program Design Industry.

An Anti-Pattern is a textual document that clearly defines a recurring situation which causes frequent mistakes in software projects. Anti-Patterns also provide solutions to avoid these mistakes when the scenario occurs. As requirements engineers see common problems, anti-patterns can be developed to reduce the risk of a poor or incomplete requirements set.

Requirements Anti-Patterns can be divided into three types:

• Gap In Knowledge - Those that guard against missing key requirements.
• Gap In Participation - Those that guard against groups that should not be involved, as well as those that ensure that the groups that should be involved, are involved at the right time.
• Gap in Process - Those that guard against omitting stages of the requirement evolution.

The objective of applying the Framework, Pattern, and Anti-Pattern to requirements is to reduce the risk of project and product failure by building a more comprehensive requirements set. The SBDi Tips of the Month will begin exploring each of these Anti-Patterns in greater detail next month.

On a more general note, SBDi recommends the following reading:

• Framework: John Zachmans information framework (http://www.zifa.com)
• Pattern: The pattern home page (http://hillside.net/patterns)
• Anti-Pattern: Brown, William, Raphael C. Malveau, Hays W. "Skip" McCormick III, Thomas J. Mowbray. AntiPatterns: Refactoring Software, Architectures, and Projects in Crisis. John Wiley & Sons, Inc. NY, NY, 2001.

The Requirements Set Framework, Pattern, and Anti-Patterns are the basis of the new book, A Requirements Pattern: Succeeding in the Internet Economy (AWL, 11/01). You can order your own copy at Amazon.com.

SBDi is available to assist your organization in understanding the detail, customizing and implementing the Framework, Pattern and Anti-Patterns.

Pat Ferdinandi