Schedule Updating and Project Control - Construction Project Scheduling and Control - page 159

though his or her fieldwork may have proceeded at a normal and decent pace. The
famous proverb, “Expect the worst and hope for the best,” can be modified in this
context as “Be conservative in your expectations and strive for the best.”
Baseline schedules may initially be prepared as summary schedules. A summary
schedule may contain only a few major components; the details are left for a later
stage. For example, a schedule prepared by the architect may include the different
design activities and milestones, with Construction represented by a single 9-month
activity. Later, when construction details are known, this activity is divided into rea-
sonably sized activities that have a combined duration of 9 months. Summary baseline
schedules are not usually used for project control. However, such schedules may be
prepared along with design development; the more you know about the project and
the more details you have in the design, the more detailed the schedule becomes.
This case applies particularly to fast-track projects (discussed in Chapter 5). With such
projects, the project manager can use the following approach: divide the project into
several phases (see Figure 5.9), with the initial (preliminary) design done for the entire
project. Later, when the detailed design for phase I is finished, the detailed construc-
tion plan, including scheduling, must be prepared for phase I while phase II is still
being designed. In this case, the detailed schedule for any phase is done just before
actual construction starts on that phase. This process provides a baseline schedule,
phase by phase.
The entire discussion on the baseline schedule applies also to the baseline budget,
with the obvious difference being that a schedule deals with time, whereas a budget
deals with money. The correlation between the two areas is explained subsequently,
when the project control concept is discussed. Another difference is the level of detail:
in schedule control, activities are connected by logical relationships. A delay in an
activity may have an effect on other activities. In budget control, the effect of a budget
overrun in an activity is mostly local and may not have a ripple effect on other activities
(unless it is attributed to an increase in the price of resources, in which case all activities
using these resources will be affected).
Oracle Primavera P6 creates baseline schedules as copies of project updates. These
“baselines” are more snapshots than baselines. This concept, which Primavera Systems
introduced, is extremely useful. It allows the scheduler to keep copies (updates) of the
schedule at different points in the life cycle of the project and to store them as inactive
copies along with the active, most recently updated schedule. The only caution is the
name: Primavera calls them baselines , but they are not baselines according to our—and
the industry's—definition.
What Is an Updated Schedule?
Schedule updating reflects actual performance information—including time of
occurrence and amount (or percentage) of work completed—on the schedule and
indicates on the schedule any changes to future work. Popescu and Charoenngam
(1995) defined an updated schedule as “a revised schedule reflecting project infor-
mation at a given data date regarding completed activities, in-progress activities, and