2Terms Duration Work Resource Resource Units Effort-Driven Fixed DurationFixed UnitsFixed WorkOver-allocationLeveling
3Duration & WorkDuration - The total span of working time or elapsed time required to complete a task.Work - The total effort required to complete a task.
4ResourcesResources are the people, equipment and supplies used to complete tasks in a project.Resources that are assigned to tasks but do not create work are known as material resources.Resource Units indicate how much of a resource's available time, according to the resource calendar, is being used to work on a particular task. In a project schedule, resource effort is expressed as assignment units or sometimes just as units.
5Duration = Work ÷ Resource Units Scheduling FormulaDuration = Work ÷ Resource Units
6Fixed UnitsAs the task's assigned units remain constant, an increase / decrease in assigned work will result in a corresponding increase / decrease in task duration.Fixed Units is the default task type for new tasks.
7Fixed Work Duration = Work ÷ Resource Units If assigned work should remain constant, then as a task's duration goes up assigned units will go down (and vice versa).If assigned units are greater than max units, a resource over-allocation will arise.Duration = Work ÷ Resource Unitsor Duration = 1 ÷ Resource Units
8Fixed Duration Duration = Work ÷ Resource Units For a constant task duration, as assigned work is increased so will assigned units.Decrease the units and the work will correspondingly reduce.Duration = Work ÷ Resource UnitsIf assigned units are greater than max units, a resource over-allocation will arise.
9Effort-DrivenOnly comes into play after the initial resource assignments have been madeWork stays constantWhen resources (manpower) are assigned or removed from a task, Microsoft Project will extend or shorten the duration of the task to accommodate change in resourcesThis is the default option for new tasks
11Over-allocationSituation when more hours of a resource are allocated than are availableIdentifying Over-allocated ResourcesSpecial leveling indicatorResource Usage View – over-allocated resources are redOver-allocation can be resolved by leveling project
12LevelingResolving resource conflicts or over-allocations by delaying or splitting certain tasks.During leveling, assignments are rescheduled according to the resource availability profiles, assigned units, and resource calendars, as well as the task's duration and constraints.It is instigated either automatically or (more commonly) by the command level now.Tools | Level Resources (hour by hour)