It’s common to misunderstand the PRINCE2 tolerances, because the term “tolerance” in PRINCE2 is not the same as one used in the common language. Let’s take a look at it.
Tolerance in the common language
When there’s a target, and you have a tolerance for it, it usually means that the goal is to reach that target, and deviations within the tolerance level would be… tolerated! The deviation is OK.
If you have many deviations within the tolerance, you would be warned, because it’s an early warning that future values might get outside the tolerance. However, you usually accept the outputs within the tolerance.
Tolerance in PRINCE2
We have targets and tolerances in PRINCE2 as well. However, we should always meet the targets and no deviation is accepted (unless otherwise mentioned in the setup). PRINCE2 tolerances are only used to show who should decide on the corrective action.
Let’s take a stage as an example. It’s planned to be done in 3 months ± 2 weeks, with €80k ± €15k.
We’re in the second week of the stage, and our forecast for the completion date is 3 months + 4 days. In this case, the Project Manager shouldimmediately think of a solution, and implement it. If the forecast is 3 months + 3 weeks, it would be outside the tolerance level and therefore the Project Board should decide on how to fix the problem instead of the Project Manager; the issue is escalated.
The same happens in other levels; for example, between the Project Manager and a Team Manager, based on the tolerances defined for the Work Package.
A PRINCE2 tolerance doesn’t say that it’s OK to have certain deviations; it’s only about “Manage by Exception”.
Setting the Tolerances
…. Read the full article at Management Plaza’s blog.