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to aggressive deadlines on project performance through adding new tasks. Figure 11 shows the
behavior of two projects (A and B) with different deadlines and, therefore, different amounts of
schedule pressure. Without schedule pressure (feedback loop R2 inactive), the two projects
finish in 25 weeks. The expected duration for project A has been reduced by 20% (20 weeks
instead of 25 weeks). Project B has had its expected duration reduced by 28% (18 weeks). The
interaction of schedule pressure and the tipping point have a dramatic impact on project
performance. Project A remains on the improving side of the tipping point and finishes, but
schedule pressure pushes Project B past the tipping point, causes trajectory reversal, and leads
to failure. Simulations verify that the amount of schedule pressure that can be absorbed without
trajectory reversal is related to the distance the project starts away from its tipping point
conditions. These simulations demonstrate that projects can absorb safely some schedule
pressure, but that in the presence of a tipping point structure, too much schedule pressure can
cause projects to fail. The added new tasks–schedule pressure reinforcing loop provides an
endogenous explanation for how projects that begin in conditions that can lead to success can
become trapped beyond the tipping point, degrade, and fail.
Total Backlog
Total Backlog
as a
as
Fraction
a fraction
of
of
Intial
initial
Scope
scope
(t)
(t)
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
Project B: Expected project duration of 28% pushes the
project over the tipping point and leads to failure.
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Total Backlog as a Fraction of Initial Scope (t-1)
Projects begins below the tipping
point.
Project A: 20% decrease in expected project
duration still alows the project to finish.
Figure 11. Effect of Schedule Pressure on Project Performance Mode
Compound Project Failure
Most development projects experience temporary problems, and many have aggressive
deadlines. In these cases, as shown above, development projects can be doomed or likely to
fail due to a tipping point structure. However, projects that can succeed despite temporary
problems but do not are of particular interest to development project managers because they
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