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6 - PROJECT TIME MANAGEMENT

6.4.3.3 Project Documents Updates

See Section 6.4.3.3 of the PMBOK Guide.
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6.5 Estimate Activity Durations

The difficulty in estimating software project activity durations is the result of many factors: intangibility of
software, broad variance in productivity of software developers, need for changes to meet emergent requirements,
the often unprecedented nature of the software product, unknown competencies of the software team, unknown
hardware or software defects, and the need to incorporate legacy software, commercial software, customer- 6
supplied software, or open-source software into the software product. Even when these factors are taken into
consideration, the result may be accurate for the known work, but cannot account for the unidentified, unknown
work that will need to be performed.

A major challenge for estimating software activity durations is the nonlinear nature of scaling software work;
a product twice as big or twice as complex, however measured, typically requires more than twice as much
work, and more than twice as much time because of the increased interdependencies of the work activities and
the increased communication among individual software developers and software teams. Adding additional work
activities may result in significant delays in the delivery of each increment of value and may result in schedule
perturbations, which future complicates the ability to accurately update estimated activity durations. The software
project life cycle and method, or methods, used to estimate activity durations should account for the significant risk
of likely estimation errors.

Because effort is the product of people and time, the schedule durations of software project activities depend
on estimated effort and available of skilled personnel resources. Section 7.2.2 of this Software Extension provides
information on additional ways to estimate effort for software projects.

6.5.1 Estimate Activity Durations: Inputs

The inputs in Section 6.5.1 of the PMBOK Guide are applicable inputs for estimating software project activity
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durations. Section 6.5.1.11 below describes additional inputs.

6.5.1.1 Schedule Management Plan

See Section 6.5.1.1 of the PMBOK Guide.
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6.5.1.2 Activity List

See Section 6.5.1.2 of the PMBOK Guide.
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©2013 Project Management Institute. Software Extension to the PMBOK Guide Fifth Edition 105
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