Anti-pattern

An anti-pattern is any common but counterproductive solution to some class of problem. The term, coined in 1995 by Andrew Koenig, was inspired by the book Design Patterns which highlights reliable and effective software development design patterns. Michael Ackroyd described anti-patterns in a paper presented at the 1996 Object World West Conference. The 1998 book AntiPatterns popularized the idea and extended its scope beyond software design to include software architecture and project management. Other authors have extended it further to encompass environmental, organizational, and cultural anti-patterns.

An anti-pattern can be distinguished from a bad habit, bad practice, or bad idea by two traits. First, anti-patterns are commonly used processes, structures or patterns of action that initially appear to be appropriate and effective, but have greater drawbacks than benefits. Second, there is another way to solve the problem that is documented, repeatable, and effective where the anti-pattern is not.

Similar to patterns, a "rule-of-three" applies: to be an anti-pattern it should have occurred at least three times.

Documenting anti-patterns can help to analyze a problem space and to capture expert knowledge. While some anti-pattern descriptions merely document the consequences of the pattern, good anti-pattern documentation also provides alternatives ways to minimize harm.