Resource Scheduling Attributes for Activities
Splitting, stretching, and reprofiling are three activity attributes that can be used to add flexibility to the treatment of an activity during resource scheduling.
Each of these techniques can be regarded as a way to improve the performance of a project by relaxing the rules of resource scheduling in a particular way.
It is also possible to assign the Immediate attribute to an activity. The Immediate attribute removes flexibility from resource scheduling calculations by forcing Open Plan to schedule an activity on the earliest date possible.
Activity Splitting
Activity splitting allows an activity duration to be split into two or more pieces. Use of this attribute may permit the activity to be scheduled earlier than would otherwise be possible due to gaps in the availability of a required resource. For example, suppose that 3 units of a resource are available on January 1 and January 2. On January 3, only 1 unit of the resource is available, and on January 4 and January 5, 3 units of the resource are again available. This is illustrated in the following profile:
Normally, a 4-day activity with a requirement of 3 units per day could not be scheduled during this period since there are not 4 consecutive days in which the necessary resources are available. As a result, either the activity must be delayed or the resource availability exceeded. If the activity can be split, however, it is possible to schedule the activity in two pieces with one 2-day piece starting on January 1 and the second 2-day piece starting on January 4.
Two parameters control the splitting of an activity during resource scheduling: the minimum duration of an activity piece and the maximum number of pieces.
Activity Stretching
A stretchable activity is an activity whose duration can be lengthened by Open Plan during resource scheduling in order to reduce the peak requirement for a constraining resource and thus obtain an earlier scheduled date. For example, assume that a 2-day activity with a requirement of 6 resource units per day is scheduled against a resource with an availability of only 4 units per day:
If the availability of the resource cannot be exceeded, Open Plan delays the activity. However, by stretching the duration of an activity to 3 days (reducing the requirement to 4 units per day), it is possible to reduce the peak requirement of the activity enough to permit the scheduling of the activity:
To control the effects of stretching during resource scheduling, Open Plan allows you to enter a maximum duration for the activity.
Activity Reprofiling
Reprofiling provides Open Plan with the most flexibility in scheduling an activity. An activity with this attribute can be scheduled in any way consistent with available resources so long as the following criteria are met:
- The duration of the reprofiled activity cannot be shorter than the specified duration.
- The reprofiled requirements cannot exceed the original requirements profile (on a cumulative basis).
Thus a 10-day activity with a resource requirement of 3 units per day cannot be reprofiled so that it has a 1-day duration with a requirement of 30 units.
To see how reprofiling works, assume that a 3-day activity has a resource requirement of 5 units per day for a total of 15 units. Depending on the availability of the resources, the activity can be reprofiled in any number of ways, including the following examples:
- 5 days at 3 units per day
- 4 days at 2 units per day, followed by 1 day at 7 units per day
- 5 days at 1 unit per day, followed by 1 day at zero units per day, followed by 1 day at 10 units per day
To control the effects of reprofiling during resource scheduling, Open Plan allows you to enter a maximum duration for the activity.
The Immediate Attribute
By assigning the Immediate attribute to an activity, you instruct Open Plan to start the activity on its earliest feasible date even if that means overloading a resource. The earliest feasible date for an activity is a date calculated by resource scheduling and represents the earliest possible date an activity can start, taking into account delays in preceding activities but in the absence of any constraints on its own resources.