Task Types Calculation (with Effort Driven & Non-Effort Driven Scheduling)
Project is constantly working to keep the following equation in balance:  	Work	=  Duration	x    Units

The task type determines how project goes about keeping it in balance.  It is dependant on one of the 3 components being fixed (the default is Fixed Units).  Another feature that works with the task types is the Effort Driven option (each task has a default of Effort Driven).  For example, when using Effort Driven scheduling, assigning additional resources to a task reduces the task’s duration (thus, the task duration is driven by effort of resources).  When not using Effort Driven scheduling, assigning additional resources to a task does not reduce the task’s duration, but will change work.  Non-Effort Driven scheduling only matters when changing the units for a task; if changes are made in other components of the formula, the rules of the task type assigned applies.

Note:  All of the following exercises start with the same “formula” components of Work 32h = Dur 16h x Units 2.  Under the original formula are the edits that were made (indicated by a format of bold)) and the results.

Fixed Units:
With Effort Driven Scheduling
Work		Duration		Units
32h	=	16h		x	2
16h	=	8h		x	2
32h	=	10.67h		x	3 

If the assigned task type is Fixed Units (default) and using Effort driven scheduling (default), then assigning additional resources will shorten the duration of the task.  Units remain at the same assigned percentage (fixed). Thus, adding resources shortens duration; deleting resources lengthens duration; units remain at assigned percent and work hours are split between resources.

Fixed Duration:
With Effort Driven Scheduling
Work		Duration		Units
32h	=	16h		x	2
16h 	=	16h		x	3 (at 67% each)

If the assigned task type is Fixed Duration, then assigning additional resources will decrease the individual unit values for resources (split between).  The duration remains the same.

With Non-Effort Driven Scheduling
Work		Duration		Units
32h	=	16h		x	2
16h	=	8h		x	2
48h	=	16h		x	3 

With  Fixed Units and Non-Effort Driven scheduling, changing the number of resources will not change the duration of the task.  Thus, duration does not change when resources are added or deleted; work is not split between resources; i.e., work hours increase if resources are added.

With Non-Effort Driven Scheduling
Work		Duration		Units
32h	=	16h		x	2
48h 	=	16h		x	3 (at 100% each)

This would be used when you don’t want to split work between resources.  For example, you have a task of a meeting with a fixed duration of 2h.  By using a task type of Fixed Duration and non-Effort Driven scheduling, you can add people to the task, keep the fixed duration and Project will not change the unit percentages.  The work (hours) will increase.

Fixed Work:
With Effort Driven Scheduling
Work		Duration		Units
32h	=	16h		x	2
32h 	=	10.67h		x	3 (at 100% each)
32h	=	32h		x	2 (at 50% each)	

With a task type of Fixed Work and Effort Driven scheduling, if resource units are added or deleted the duration is changed; however, the work hours will remain fixed.  If the duration is manually changed, units will split the work hours (percentages will be effected).

Non-Effort Driven Scheduling

With a task type of Fixed Work, you can only use the Effort Driven scheduling method.  In a non-effort driven method, when a change is made to the units, it will not affect the duration, but it does affect work.  Therefore, with a fixed work task, there is not the ability to have a non-effort driven scheduling method.