Brad Bigelow, a PRINCE2 V7 author, emphasizes the importance of tolerances in the PRINCE2 project management framework, describing them as one of its "secret sauce ingredients." He explains that tolerances provide a control mechanism that empowers project managers (PMs) to make tactical decisions without constantly seeking approval from the project board or executive members. This aspect of PRINCE2 recognizes that while executives are intermittently involved in a project, PMs are engaged on a day-to-day basis.

Tolerances are set to define the limits within which PMs can operate autonomously. For instance, a project might have a 10% cost tolerance, allowing the PM to make financial trade-offs and adjustments within this range. This flexibility is crucial for dealing with the inevitable variations and unforeseen issues that arise during project execution. However, Bigelow notes that this autonomy is not unlimited. Should the PM anticipate exceeding these tolerances, they are required to escalate the issue to the project board for higher-level decision-making.

Bigelow highlights that this approach to managing project tolerances is not only practical but also beneficial for many organizations. It strikes a balance between giving PMs the freedom to manage day-to-day operations effectively and ensuring that significant changes or deviations are subject to executive oversight. This system of checks and balances is fundamental to the successful application of the PRINCE2 methodology in project management.