As indicated in the basic control cycle, in case of deviations, changes to the original plan might become necessary.
On this page we explain how we can control these changes.
Some of the deviations - and thus, the resulting changes - may be
due to errors or misinterpretations of the original plan;
others are due to external influences or events in the project
However, changing the plan often leads to project delays or additional cost which we want to minimize as far as possible.
If we have done comprehensive risk analysis in project planning phase then we might be in the lucky situation that most of those events
might not happen because of preventive actions, or their consequences are covered by (well prepared) corrective actions.
Let us pick up our "desk example" and follow the sequence of events during implementation phase.
As a reminder, here is the desk gantt chart with milestones:
Now follow the sequence of events:
Comments, referring to the basic control cycle:
Event 1: Result of comparison: Actual length of
desk top is only 198 cm instead of 200 cm. Decision: change
specification of result and change the plan.
Event 2: Drill bit breaks. This was an item in our risk analysis and we took preventive action. Therefore, no further impact.
Event 3: Timber connectors break. This was not
covered by our risk analysis. Our best option was to stick with the plan
and do the work again.
Event 4: Glue needs more time to dry. This was
not covered by our risk analysis. Our best option was to change the time
schedule for the corresponding work packages,
without any time delay to the project, since glue can dry over night.
This example shows that we cannot plan for every eventuality of
real life, even with careful risk analysis. As pointed out earlier, it
is particularly difficult to set up a WBS
that is complete, i.e. that contains all the work necessary. For this, we need advice of experienced experts.