Crystal Family

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Crystal Light is a family of software - development methods , to the agile methods is expected to software development. The methods of this family are usually labeled with colors. The simplest variant, however, is called Crystal Clear ('crystal clear').

Crystal principles

Passive knowledge transfer
Informal, "passive" knowledge transfer is promoted through spatial proximity and freedom for discussions.
Personal security
Criticism and fears can be expressed without reprisals.
Ongoing criticism and improvement
Suggestions for improvement are constantly sought, collected and the importance of their implementation assessed.
Focused work
Employees know exactly what their goal is and are not distracted or pulled away for other projects.
Frequent releases
Frequent release of intermediate versions to the customer or other project participants prevents expectations from building up and greater need for explanation. At the same time, interim approvals can provide greater security for the team.
Access to knowledgeable users
Because an experienced user of the future product is always available, detailed questions can be clarified quickly and informally. Among other things, this prevents misunderstandings from growing into problems.
Automated testing
By unit testing is ensured permanently stable program code, which also strengthens the confidence of the team in their own work.
Frequent integration
Not only the program code is tested, an executable test version is also created regularly (e.g. daily and automatically).
Configuration management
Use of configuration management , or at least version management .

The crystal variants

Crystal is not a single method, but - as mentioned - a family of methods with variants.

The purpose of this subdivision is that, on the one hand, a set of rules that fits the project circumstances can be selected and, on the other hand, these rules do not have to be negotiated and defined individually.

Division into variants

The choice of the crystal variant depends on the number of people involved and the criticality (level of risk).

The methods are named with colors: Crystal Clear , Crystal Yellow , Crystal Orange , Crystal Orange Web , Crystal Red , Crystal Magenta / Maroon , Crystal Diamond (optional), Crystal Blue , Crystal Sapphire (optional). The color essentially reflects the number of people. The simplest variant, Crystal Clear, is recommended for team sizes of two to six people.

Criticality, on the other hand, depicts the risks, i.e. what type and extent of damage is to be expected in the event of a project failure. Depending on the criticality, a "degree of hardness" is selected for the respective crystal variant. The following levels of criticality are defined in Crystal: endangering customer satisfaction, loss of money, damage to image, and the highest level: loss of human life.

Depending on the selected Crystal variant, the number of roles, the number of methods to be used and the scope of documentation change.

The classification according to criticality and number of employees takes place according to the following scheme:

Choice of variant

Program defects

mean danger to

Number of participants
1-6 6-20 20-40 60-100
Life - - - -
Critical funds - E20 E40 E100
Available funds D6 D20 D40 D100
Comfort C6 C20 C40 C100
methodology used Crystal clear Crystal Yellow Crystal Orange Crystal Red

As soon as the criticality "critical money" has been reached, ie when it comes to financial losses that could endanger the continued existence of a company, at least the "crystal yellow" method should be selected. In the criticality of "life" (ventilation of submarines, elevator control ...) Cockburn says he has no experience - he therefore does not recommend any method.

The grouping according to the number of employees is justified by the fact that the communication effort must be structured differently as the number of employees increases. While a team of six people can be rounded up informally at any time (physical proximity is given according to the principles), with a team of 20 people you have to determine a point in time. With 60 people, however, a joint discussion is unrealistic.

Different forms and means of communication are proposed for each of the group sizes.

The grouping by criticality, on the other hand, affects how formal and precise the approach is. The more serious the risks, the more additional work is required for the correctness and security of the program. Here, too, there is a staggering of the methods to be used.

By combining the two criteria, the short name of the specific variant can be found, the details of which can then be looked up directly and clearly. This allows adaptation to the project circumstances without having to negotiate for a long time which rules should apply in the present case.

Comparison with other agile methods

In relation to other agile methods (such as extreme programming ), crystal is seen by its proponents as less dogmatic and formalized. With Crystal Clear, pair programming or customer on site (' customer on site', means a representative on the development team) is never required.

One can say more neutrally that Extreme Programming is about the way you work, whereas Crystal is oriented towards the individual project .

Crystal does not introduce permanent methods for the team, but determines the methods to be used for each individual project. In the case of simpler projects, this can mean that many of the agile methods also used in XP are used; For more complex projects, a variant would be used that is more similar to more complicated process models .

literature

Web links

Individual evidence

  1. ↑ Lajos Jenő Fülöp, Péter Körtvélyesi: IT support for project management processes. 5.4 Crystal methodology - According to project size & criticality. Faculty of Computer Science. University of Szeged, May 28, 2019, accessed June 30, 2014 (English).