Task Type and Effort Driven Options in Microsoft Project
If you are not sure which option to use then I recommend Non Effort driven as a default. This option prevents changes to Task Durations and/or existing Resource assignments as Resources are added or removed from a task.
* Select Fixed Units for activities when the Units per time period must stay constant as either the Duration or Work is changed. For example, a crew of 1 Excavator and 3 Trucks must stay constant as the Duration or Work is changed.
* Select Fixed Duration for activities when the duration must not change as either resource Units per time period or Work is changed.
* Select Fixed Work if you wish the Work to stay constant as the duration is changed. The Task will be made Effort driven automatically with the Effort driven option grayed out. For example, a programmer assigned full-time for a week will have 40 hours’ work.
When the duration is doubled to a week, the programmer will work 50% of the time over 2 weeks but still work 40 hours. If you assign another person to help then the total Work will remain at 40 hours and the Duration not change.
The default for new Tasks is set in the Tools, Options…, Schedule tab. Click on the icon and new projects will have these as their default options.