Task Types and Effort Driven

The variables for each activity are initially calculated the same depending on the order in which you enter information. However, if you modify the scheduling attributes of an existing activity, how the activity values are recalculated is controlled by the task type.

• If your project planning process does not include resource assignments, you can disregard the Task Type and Effort Driven attributes.

• The task type does not prevent you from modifying the fixed variable; it only controls how Windchill recalculates the scheduling variables if you later modify the activity. For example, you can still modify the work in a Fixed Work activity.

• By default, summary activities are set to the Fixed Duration task type and cannot be changed. A summary activity is calculated based on information set for its child activities. However, each child activity can have its own task type.

The task type determines whether the Duration, Work, or Resource Units value should remain fixed when you modify the activity schedule attributes.

Fixed Variable	Resource Units
Calculated Variables	Duration Work
Use Case Example	You plan an activity and assign as a resource an employee who only works 2 hours each day. Therefore, this resource can only be allotted 25 resource units. If you use the Fixed Units task type, you can add or remove work or change the estimated finish date without affecting the fact that the employee can only spend 2 hours each day on that project.

The effort required for an activity (typically assessed in terms of how many hours it should take) does not change regardless of resource units or duration.

Fixed Variable	Work
Calculated Variables	Resource Units Duration
Use Case Example	You need to make 160 plastic molds and know that since it takes a resource 1 hour to make 10 molds, then the work should take 16 hours. You assign a resource who can work 8 hours each day, and the activity duration is calculated as 2 days. If you use the Fixed Work task type, you can change the duration or modify how much time the resource can spend on the activity each day without changing the fact that the activity will still require 16 hours of work to complete. Adding more days to the duration means that the resource can spend less time each day making molds. Removing resource units means that the activity will take more days to complete.

Fixed Variable	Duration
Calculated Variables	Resource Units Work
Use Case Example	You create an activity to represent a professional conference that lasts 5 days. If you use the Fixed Duration task type, you can change how many hours should be spent working at the event while keeping the activity duration as 5 days.

Task Type	Modify Units	Modify Duration	Modify Work
Fixed Units	Duration changes	Work changes	Duration changes
Fixed Work	Duration changes	Resource Units changes	Duration changes
Fixed Duration	Work changes	Work changes (by default)	Resource Units changes

The Duration Change for Fixed Duration Task Type preference controls whether work or resource units are affected when you modify the duration of a Fixed Duration activity. By default, the work is recalculated. For more information, see Project Planning Preferences.

The Effort Driven field determines what variable is affected when you add or remove activity resources. This is treated differently than when you modify resource units.

An effort-driven activity indicates that the amount of work required to complete the activity does not change regardless of how many resources are assigned. When additional resources are assigned to an effort-driven activity, either the activity duration or the units assigned to each resource are recalculated accordingly.

• An effort-driven activity might be if you got an order for 2000 boxes. Your resources can assemble 10 boxes per hour, meaning that this activity represents 200 hours of work. With 1 resource spending 8 hours each day on this activity, it will take 25 workdays to complete. If you assign a second resource, then it will only take 12.5 workdays to complete. If you assign a third resource, it will only take 6.25 workdays.

• A non-effort driven activity might represent a specific assembly line over a span of 5 days. With one resource assigned to work 8 hours each day on that assembly line, the activity represents 40 hours of work. If you hire another resource to work along the assembly same line, then that activity represents 80 hours of work.

Task Type	Affected Variable
Task Type	Effort Driven	Not Effort Driven
Fixed Units	Duration Assigning a new resource means that the activity takes less time.	Work Assigning a new resource means that the activity represents more work hours spent.
Fixed Work	Duration Assigning a new resource means that the activity takes less time.	—
Fixed Duration	Resource Units Assigning a new resource means that the assigned resources can spend less time each day working on the activity.	Work Assigning a new resource means that the activity represents more work hours spent.