A reader asked me how to do high-level resource planning rather
than a bottom up resource plan. This is a common problem when project managers
first try to estimate budgets, high-level timelines, and the resources required
to complete a project. This type of planning is usually done in Microsoft Excel
with rough estimates, but you can use Microsoft Project 2010 to
develop a useful resource model.
In this high-level planning example, a typical task can be
10,000 hours of work that needs to be delivered between 3 and 12 months. For
any given project, there are 5 to 10 of these tasks. Using the hours and variable duration, the project manager
wants Microsoft Project to calculate the number of resources needed to deliver
the project. I simulated several projects using the reader’s requirements using
the following steps.
Set up Project Options
For this resource model, set up the Project Options as follows:
- Set Show Assignment Units As A Decimal.
- Duration Is Entered In Days.
- Work Is Entered In Hours.
- Default Task Type is Fixed Work (Figure A).
Figure A (See an enlarged view of the image.)
Create the model
- Create three tasks with the Fixed Work type.
- Enter 10,000 hours for the Fixed Work effort.
- Enter a 90 day, 120 day, or desired duration.
- Add predecessors if necessary.
- Assign only one
resource name to all of these tasks.
The project schedule should look like Figure B.
Figure B (See an enlarged view of the image.)
By assigning the same resource name to all of the tasks, the
resource will be overallocated. That’s okay, because we will use the Resource
Graph to determine the number of resources needed to realistically complete the
View the Resource Graph
- Switch to the Resource Graph by selecting View |
- Right-click the graph and confirm Peak Units is
selected (Figure C).
Figure C (See an enlarged view of the image.)
The Resource team member is overallocated. By examining the
peak units, I know I’ll need 32.64 or 33 resources to actually work on the
project if the team is expected to complete 10,000 hours worth of work in 90
days. The same amount of work across 120 days would take 18.75 or 19 resources,
and if the team had five months to complete the work, the project would require
8.33 or 9 resources.
At a macro planning level, this model doesn’t take into account
specific project roles or existing team commitments; however, it is a quick way
to estimate effort based on the work calendar, estimated effort, and mandated
durations. A similar calculation can be derived in Microsoft Excel, but
Microsoft Project also provides the project forecasting based on effort-driven
estimates and resource constraints.
Microsoft Project is often used for task scheduling, though you
can build more complex resource models in it to support portfolio planning, resource
estimation, and resource management by skill set. I’ve applied similar models
to manage new project demand and make prioritization decisions based on the
existing work in the portfolio pipeline.
The project schedule is simply a planning model used to
forecast future events based on past accomplishments; the model will adjust
throughout the project. These models can be applied to more than just a single
project schedule — they can also be applied to estimating effort and managing
work across a portfolio.
Go ahead and give it a try. You’ll likely switch from Excel
formulas to a more accurate resource model.