What is a Quality Gate, which prerequisites must be met for its application and what are its application scenarios?
Using Quality Criteria for Progress Decisions
A Quality Gate is a special milestone. It emphasizes the qualitative aspect of the results at a defined point in time in a project. The Quality Gate will be passed when all defined quality criteria are fulfilled and a committee makes a positive decision on the progress of the project.
Milestones divide the course of a project into verifiable sections such as project phases. Milestones thus facilitate both project planning and project implementation or control. In contrast to a “conventional” milestone in organizations, in which the temporal aspect is often in the foreground – defined results must be produced on defined dates – a Quality Gate places the qualitative aspect in the foreground. Only when predefined quality criteria have been met the subsequent project phase can be approved.
Prerequisites of Quality Gates
There are two essential prerequisites for the use of quality gates:
- A sequential procedure in a phase model, so that the phase transitions take place in a predefined sequence. (In practice, this does not necessarily mean that activities in subsequent phases cannot be started in advance. If there is no phase release, however, the risk increases that the activity will become useless if phase release is refused.)
- A binding agreement on quality criteria before the start of a phase. Since projects often cannot be planned in detail from start to finish, it is not unusual in project management practice to define quality criteria for individual phases only in the course of the project. This also emphasizes the idea of quality in the progression of the project and minimizes problems such as the 90% syndrome. Even if quality gates can be used for quality control and quality measurement, companies should not define too many quality gates. The respective definition of the quality criteria and the acceptance of the results can be very time-consuming and in the worst case delay the progress of the project.
Application scenarios of Quality Gates
A relatively typical application scenario is testing the maturity level of a component development at a defined point in time. Here, the concept of quality gates helps to ensure on-time deliveries or to identify possible delays. This is made possible by fixing the time of the gates. It is also used in the context of regulatory requirements, e.g. in projects with high risks to life and limb, health and the environment. Often, corresponding audits are carried out by authorities, so that a big difference to milestones becomes clear: In the case of an external audit, the internal productive work is usually suspended.
If it is not an external audit, a suitable committee should decide at the end of each phase, e.g. in the context of a project review, whether the project may pass the gate to the next phase or whether improvements are necessary. In the PRINCE2 project management method, such a body would be the steering committee.