Scheduling as Part of the Project Management Effort - Construction Project Scheduling and Control - page 287

Oracle Primavera P6, for example, is a product designed for the “enter-
prise,” with a multiproject management capability. 19 It offers three breakdown
structures:
a. The EBS (enterprise breakdown structure) is a breakdown for the corpora-
tion (enterprise). Typically, this structure includes the departments in the
organization. Each department can be broken down further into sections
and so on, where projects reside.
b. The OBS (organizational breakdown structure) is a breakdown of the func-
tional responsibilities. Typically, you tie the EBS to the OBS to define peo-
ple, along with their departments (who does what).
c. The WBS (work breakdown structure) is a typical project breakdown struc-
ture (PBS). Unlike the EBS and the OBS, the WBS is at the project level,
and it can differ from one project to another.
TIME CONTINGENCY AND MANAGEMENT OPTIONS
When a scheduler or a PM creates a schedule, he or she must include a time contin-
gency that represents the expected nonworkdays. This time contingency includes two
types of nonworkdays:
1. Known dates, such as holidays and planned shutdown days : The scheduler must
enter these days in the calendar of the computer program. The computer
program will not allow any work on an activity on such days (provided the
activity uses that calendar).
2. Unknown dates : The scheduler should typically expect some occurrences that
will prevent work from taking place, such as severe weather conditions or
accidents. For example, for a 1-year project, the scheduler might allocate 18
nonworkdays. This 18-day schedule contingency can be considered total float for
the entire project, in addition to the calculated total float. It can be handled in
one of the following two ways, or a combination of both can be used:
a. Allow the crews to control this float : In this case, the durations of all activities
are stretched by a percentage that extends the entire schedule by 18 days.
This is not a recommended option, because human nature makes the work-
ers stretch work to fill the given time span. As an alternative, the PM may
assign these 18 days to certain activities according to his or her discretion.
b. Give management control of these days and allow them to “be spent” as needed :
Management must be careful not to use such time contingency days to
19 As mentioned in chapter 7, Microsoft has developed solutions, such as Microsoft Enterprise Project
Management (EPM) Solution for project and portfolio management.