Certificate IV Project Management - Activity Duration Estimating (Inputs)
Learn about Activity Duration Estimating
(Inputs) in the Certificate IV Project
Enterprise Environmental Factors
One or more of the organisations involved in the project
may maintain duration estimating databases and other
historical reference data. This type of reference
information is also available commercially.
These databases tend to be especially useful when activity
durations are not driven by the actual work content (e.g.,
how long it takes concrete to cure or how long a
government agency usually takes to respond to certain
types of requests).
Organisational Process Assets
Historical information on the likely durations of many
categories of activities is often available. One or more of
the organisations involved in the project may maintain
records of previous project results that are detailed
enough to aid in developing duration estimates. Historical
information can come from several sources, including
project files from other projects, commercial duration
estimating databases, project team members, and other
Project Scope Statement
The constraints and assumptions from the project scope
statement are considered when estimating the schedule
activity durations. An example of an assumption would be
the length of the reporting periods for the project that
could dictate maximum schedule activity durations.
An example of a constraint would be document submittals,
reviews, and similar non-deliverable schedule activities that
often have frequency and durations specified by contract or
within the performing organisation’s policies.
Activity lists are the work elements necessary to create
Effort is the amount of labour applied to a task. Duration, on
the other hand, is how long the task is expected to take with
the given amount of labour. For example, a task to unload a
freight truck may take eight hours with two people assigned
to the task.
If the effort is increased by adding more labour to the task
(in this instance, more people), then the duration of the task
is decreased. Some activities, however, have a fixed duration
and are not affected by the amount of labour assigned to
For example, to install a piece of software on a computer
will take the same amount of time if one computer
administrator is completing the work or if two computer
administrators are doing it.
Activity Resource Requirements
Activity resource requirements define the resources that are
needed to complete a particular activity. For example, a
project to build a home will require lots of different resources:
plumbers, electricians, architects, framers, and landscapers.
The project manager would not, however, assign all of the
different resources to every task, but only to the tasks that
the resource was qualified to complete.
However, as additional resources are added or lower skilled
resources are applied to some schedule activities, projects
can experience a reduction in efficiency. This inefficiency, in
turn, could result in a work production increase of less than
the equivalent percentage increase in resources applied.
The composite resource calendar, developed as part of the
Activity Resource Estimating process, includes the
availability, capabilities, and skills of human resources. The
type, quantity, availability, and capability, when applicable,
of both equipment and materiel resources that could
significantly influence the duration of schedule activities
are also considered.
For example, if a senior and junior staff member are
assigned full time, a senior staff member can generally be
expected to complete a given schedule activity in less time
than a junior staff member.
Project Management Plan
The project management plan contains the risk register
and project cost estimates.
The risk register has information on identified project risks
that the project team considers when producing estimates
of activity durations and adjusting those durations for
risks. The project team considers the extent to which the
effects of risks are included in the baseline duration
estimate for each schedule activity, in particular those
risks with ratings of high probability or high impact.
Activity Cost Estimates
The project activity cost estimates, if already completed,
can be developed in sufficient detail to provide estimated
resource quantities for each schedule activity in the
project activity list.
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