Monday, December 17, 2012

The Schedule – Resource Assignments

“Time is the scarcest resource and unless it is managed nothing else can be managed.”
                                                                                                                - Peter Drucker

We are now half way through the steps for creating a well-formed schedule.  In my previous post in this series, we added task effort estimates, but we have not yet added resource assignments, which we will now do.
Why add task estimates without considering the resource assignments and then immediately follow that step with the step that adds the resource assignments and then re-estimate each task specifically for the resource?  Let’s consider three scenarios:

For a small, routine project in a fully staffed environment, assigning resources may be a mechanical exercise (you’ve probably done this same type of project so often, the WBS was built practically from a template and you know exactly who is doing each task).  I’ll come back to this first scenario later.
A second scenario is more common:  It is a large project, but some of the resources are known (or the resource skill is known and easily acquired).  However, for some tasks, there may be choices or the resource may not be known until late in the planning cycle.

A third scenario could be a large project, but it is one where the resources are definitely not known and there could still be many negotiations about staffing options.  In fact, the budget, schedule and scope could still be under negotiation.  But a time and cost schedule is needed to get approval to acquire the resources.
For a best practice recommendation, it must be general to all possible cases.  Since it isn’t always possible to know the resources and sometimes it is necessary to have estimates without resources, the general case is to first build the schedule with estimates but not resources.  Then when appropriate, add the resources and re-estimate.

For the first scenario, you certainly can combine these two steps.  Just understand that you are taking a short cut and that in other circumstances or a different environment you will want to follow the best practice.
Getting back to this step, then, you have a partially built schedule with dependencies and estimates, but no resources (or possibly generic resources).  So start assigning resources to tasks (or substituting resources for generic resources), ignoring, for now, resource conflicts and over-allocations.  For each resource assignment, review the task (inputs, outputs, work products, completion conditions, etc.) with the resource and have them re-estimate the task based on their understanding.  Review with the resource any task where there is a significant difference between the original estimate and this new estimate to understand why.  Update the task estimates with these revised values.

Don’t be surprised to find that the new estimate from this step is significantly different from the previous estimate and that you may need to renegotiate budget and scope expectations.  You may even find that as you complete some resource assignments, it forces changes to other previous or planned assignments.  And be prepared for even more variance in the next steps.  That’s why this is a recursive process – it seems like you just keep starting over from the beginning.
But actually, we’re up to Resource Leveling, the next to last step in building the well-formed schedule.  This is the subject of my next post.

Do you have resources estimate their own tasks?

No comments:

Post a Comment