Why is crystal called a family of agile methods?

Answer 1

mahdi rohani.

Alistair Cockburn has long been one of the principal voices in the agile community. He developed the Crystal family of software development methods as a group of approaches tailored to different size teams. Crystal is seen as a family because Alistair believes that different approaches are required as teams vary in size and the criticality of errors changes.

Despite their variations all crystal approaches share common features. All crystal methods have three priorities: safety (in project outcome, efficiency, habitability (developers can live with crystal). They also share common properties, of which the most important three are: Frequent Delivery, Reflective Improvement, and Close Communication.

The habitability priority is an important part of the crystal mind-set. Alistair's quest (as I see it) is looking for what is the least amount of process you can do and still succeed with an underlying assumption of low-discipline that is inevitable with humans. As a result Alistair sees Crystal as requiring less discipline that extreme programming, trading off less efficiency for a greater habitability and reduced chances of failure.

Despite Crystal's outline, there isn't a comprehensive description of all it's manifestations. The most well described is Crystal Clear, which has a modern book description. There is also a wiki for further material and discussion of Crystal.