Useful techniques to fine-tune your project schedule

By ExecutiveBrief Staff

How do you use CPM to fine-tune your schedule?

Slack Time
Slack time, as the name implies, is the time when one can relax, delay a task but still the project is finished on time. A more formal definition from the Project Management Body of Knowledge (PMBOK) is “The amount of time that a schedule activity can be delayed without delaying the early start of any immediately following schedule activities.”.  Slack time is such an adverse-sounding term that managers tend to remove them in the schedule and present one that does not contain it to impress their bosses or clients.  While this may look good on the surface, there are consequences when reducing slack times is not done properly.

For starters, accept the fact that slack times are a normal phenomenon in project schedules. The role of a manager is to identify and minimize them.  By identifying the slack time, a manager becomes aware in keeping estimates and dependencies accurate. Once there is acceptance, start thinking of ways to reduce slack times and improve productivity.  Determining the best strategy separates experienced managers from the novice, but some of the common ways are:

• Give additional task to the resource assigned during the slack time.
• Ask the resource to help out in other critical tasks.
• Share the resource with another project.

Crashing
Crashing is the process of fine-tuning your project schedule to shorten delivery time. It is a possible solution when stakeholders ask for a faster delivery while not willing to reduce the scope of work. So, how does crashing work? Simple. Reduce the time to complete the tasks in the critical path. Note that crashing works only on tasks in the critical path because reducing time on non-critical tasks will not affect the project delivery time. Do not waste your time crashing non-critical path tasks; instead, crash on tasks in the critical path to get immediate results.

You can think of several ways to crash a task. You can put two resources to work in parallel and have the task completed in half the time. Or you can assign a more productive resource who can finish the work earlier. In any case, make sure you assess the risks. There are tasks that cannot be performed by two persons, like installing a software or hammering a nail. Also, make sure you are not over-assigning critical tasks to your best resource, because he can only be 100% productive and anything above it will be counter-productive. It is mindless to assume that your best resource can work 16 hours a day for the next three weeks.

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