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Project Definitions
Calendar
A calendar defines the working days and hours during which tasks can be scheduled. A base calendar is
used to schedule work on tasks to which no resources have been assigned. A resource calendar is used to
schedule work on tasks according to a resource’s specific availability.
Task
A task is an activity or event that must be completed for the project to be completed. Tasks must have
definite beginning and ending points. A task can be a broadly defined group of activities or a very
narrowly defined specific event.
Summary Task
A summary task combines and summarizes the duration, work and cost of subordinate “detail” tasks. For
example, a summary task called “Training Phase” might summarize tasks such as Write Training
Materials, Schedule Students, and Conduct Training Class.
Milestone
A milestone is a goal, checkpoint, or important date in the project. Milestones are generally used, for
example, to mark the beginning and end of major phases of the project. Generally, a milestone is a task
with a duration of zero.
Dependency Relationship
A dependency relationship describes the link between task’s scheduled start or finish and the scheduled
start or finish of a predecessor task. A dependent task is called a successor. For example, when building a
house, pouring the foundation is a predecessor to building the walls.
Lag Time
Lag time is a delay between a task and its predecessor. For example, if a supplier sends satisfaction surveys
to its customers, the supplier might plan for lag time between mailing the surveys and receiving the results.
Lead Time
Lead time is an overlap between a task and its predecessor. For example, an analyst does not need to wait
until all of the information is received to begin writing the report. There can be planned overlap between
the tasks Collect Data and Write Report.
Task Constraint
A task constraint is a restriction or limitations set on the start or finish date of a task. Normally tasks are
considered unconstrained and are scheduled with the default constraint of As Soon As Possible. If a
meeting date or critical activity needs to occur on a particular date, a Must Start On constraint could be
used.
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Duration
The duration is the amount of calendar time from the start to the finish of a task. For example, the task
“Write Report” might have a duration of 4 days.
The task duration can be entered by the project manager or can be calculated by the software based on the
resource effort required to complete the task and the availability of the resource.
Resource
People or assets that perform work on tasks are defined as resources. Examples include an individual, a
team of workers, a piece of equipment, a facility, or an outside vendor or contractor.
Work
Work is the amount of effort required by resource assigned to a task. Units can be expressed as a
percentage or as a decimal. For example, one carpenter working full-time on a task would be assigned 1
unit or 100%. If the carpenter could only work half of the time, the unit would be .5 or 50% on the task.
The Max. units is the maximum number of resources available full time on a project, the maximum units is
3 or 300%.
Scheduling Method
The scheduling method refers to the calculation strategy that Microsoft Project will take when assigning
more than one resource to a task. When assigning resources, it is important to use the scheduling method
that best suits the individual task.
Effort driven tasks are those tasks for which the amount of work required remains constant and the
duration varies as the number of resource units assigned to complete the task is changed. For example, it
might take one resource 16 hours to pack boxes. The duration of the task would be 2 days. If an additional
resource was assigned to the task the 16 hours of work would be split so that each resource performed 8
hours of work and the duration of the task would be cut in half to 1 day.
Non-Effort driven tasks are those tasks for which the amount of work is varied and the duration remains
constant as the number of resources assigned to complete the task is changed. For example, one resource
might be assigned to attend a training seminar for 1 day representing 8 hours of work. If another resource
is assigned to the training seminar, that resource is scheduled for an additional 8 hours of work while the
duration of the class remains the same.
Overallocated Resource
A resource is overallocated when the resource’s Peak Units are greater than the resource’s Max. Units at
any one time. In other words, the work assignments for an overallocated resource require more work
during a specific time period than the resource can provide. For example, a resource is overallocated if the
resource is assigned at 100% or 1 unit to two tasks at the same time.
Resource Leveling
Resource leveling is Project’s tool for delaying or splitting one or more tasks that are competing for an
overallocated resource in order to resolve the demand for the resource.
Slack Time
Slack time is the amount of time that a task can be delayed without affecting the project’s completion date
(total slack) or the scheduling of any other task (free slack). Microsoft Project calculates slack time for all
project tasks based on the duration of the tasks and task dependency links.
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Critical task
A critical task must be completed on time in order to complete the project on schedule. Critical tasks have
no slack time.
Critical Path
A critical path is the sequence of tasks that determines the earliest time that the project can be completed.
None of the tasks on the critical path has slack time.
Noncritical Task
A noncritical task may be delayed to some extent without affecting the project’s completion date. A
noncritical task has slack time grater than zero.
Baseline
The baseline is the original schedule for a project used for comparison purposes as actual information
develops and is added to the project.
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