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Unformatted text preview: t time. It also allows informed decision making by
management. Thus, CPM, used properly, can be an invaluable tool. Constructing an Arrow Diagram
As I pointed out in Chapter 4, before scheduling is done, a Work Breakdown Structure (WBS) consisting of
from two to twenty levels should be developed. To illustrate how a schedule is constructed from a WBS, we
consider a simple job of maintaining the yard around a home. The WBS is shown in Figure 5-3.
It is appropriate for this WBS to schedule the tasks at the lowest level. This, however, is not always true. It is
possible, for example, that you may break down the work to level 6 but enter only those activities up to level
5 into the schedule. Figure 5-3 Work breakdown structure for yard project.
A good rule of thumb to follow is that no task should have a duration much greater than four to six weeks.
The reason for this is that you may not be able to keep level six tasks on schedule; you may not be able to
manage that tightly. So you schedule at a level that you can manage. This follows the general rule that you
should never plan (or schedule) in more detail than you can manage. Some projects, such as overhauling a
large power generator, are scheduled in increments of hours. Others are scheduled in days, while some big
construction jobs are scheduled to the nearest month.
Don’t schedule in more detail than you can manage.
While planning in too much detail is undesirable, if you plan in too little detail, you might as well not bother.
As a practical example, a manager told me that his people wanted to create schedules showing tasks having
twenty-six-week durations. He protested that they would never complete such schedules on time. They would
back-end load them, he argued. Previous Table of Contents Next www.erpvn.net Products | Contact Us | About Us | Privacy | Ad Info | Home
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EarthWeb is prohibited. Read EarthWeb's privacy statement. www.erpvn.net Fundamentals of Project Management
by James P. Lewis
ISBN: 0814478352 Pub Date: 01/01/95
Search Tips Search this book: Advanced Search Previous Table of Contents Next Title What he meant was that there is a lot of security in a twenty-six-week task. When the start date comes, if the
person doing the task is busy, she might say, “I can always make up a day on a twenty-six-week activity. I’ll
get started tomorrow.” This procrastination may continue until she realizes she has delayed too long. Then
there is a big flurry of activity as she tries to finish on time. All the work has been pushed out to the end of the
twenty-six-week time frame. ----------- A good rule of thumb to follow is that no task should have a duration much greater than four to six weeks. A
twenty-six-week task can probably be broken down into five or six subtasks....
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This document was uploaded on 09/27/2013.
- Fall '13