One of the PRINCE2 principles is the Manage by exception. The project manager manages the
project and tries to keep the project within its budget, deliver the project on time and in required
quality. For these aspects the project manager has defined boundaries within which he or she can
act. If these limits are exceeded then project board involvement is required. Additional boundaries
are specified by the project manager for the development team. The development team also acts
in defined limits and when these limits are exceeded then it must be escalated to the project
manager. These limits can be set for example to: minimum number of stories/features to be
delivered in the sprint, acceptable deviation for the sprint progress based on the burndown chart
and also for the criticality of the identified risks.