It is typical that when a project or programme is being planned, that the project manager has to make a number of assumptions in order to create the initial project schedule, budget, resource and benefit profile.  The reason this is necessary, is that in the early stages, a lot of the detailed analysis will not have been completed (or even started).

The use of assumptions allows for initial plans to be constructed without investing the time, budget and resources in completing the detailed analysis.  This is good for the sponsor as it means they can get an estimate without having to invest to have the detailed analysis completed.  This in turn should allow for an informed decision to be made.

If assumptions are going to be made to support the estimates, it is important that they are accurately documented.  This will allow them to be reviewed by all stakeholders to establish if they are comfortable with the assumptions.

In order to support this, the PMO should ensure that there is a recognised process to capture and document assumptions.  This will normally be in the form of a register, usually in table or spreadsheet format.  It should allow important details to be collected about the assumption to be listed including:

  • Assumption name
  • Description
  • Date identified
  • Identified by
  • Impact if assumption is incorrect
  • Owner
  • Target resolution date

The PMO should check to make sure that each project is capturing and documenting assumptions using the defined process.  It is also sensible for the PMO to review the assumptions before they are formerly presented to the sponsor.  This will allow for the assumptions to be tested and refined.  This should be seen as helping the project manager NOT trying to catch them out!

While it is important to capture assumptions during the planning process, it is also critical that assumptions are proven to be correct or not correct as soon as possible.  For example, if a project schedule and budget has been based on the assumption that a new accounting process will be able to be used on a global basis meaning only a single software program needs to be written, then it is important to prove this assumption is true.  If not, it may be necessary to build several versions to support the accounting processes for a number of countries.  This will result in increased time and costs and may make the project not viable.

Due to the risks in assumptions proving to be incorrect, the PMO should make sure that each project is taking the action to prove the assumptions.  The PMO should regularly review the assumption log with the project manager and track if the assumptions are being closed out in line with the target dates.


  • The PMO should define an assumption process and tools.
  • The PMO should review the initial assumptions with the project manager.
  • The PMO should regularly monitor that assumptions are being closed out in a timely manner.

For more details, take a look at post PMO tools – Risk, Assumptions, Issues, Dependencies.