The duration or work value changed when i assigned a resource

Symptoms

The duration, work, and resource assignments for a task are interlinked. When you assign resources to a task, Project calculates how long the task is likely to take to complete using those resources. If you assign multiple resources at the same time, the duration doesn't change from your original estimate. But if you change the number of resources for a task that already has an assignment, Project calculates how much time it will take with these resources and will decrease or increase either the task's duration value or its work value, based on the task type. This is known as effort-driven scheduling.

For example, if a task with a four-day duration is assigned to two resources, the duration stays at four days, and each resource is assigned to work on the task for four days. However, if you assign two additional resources, the duration decreases to two days because the duration is expected to be half as long with twice as many resources.

When you assign an additional resource to a fixed-duration task that already has assigned resources and that uses effort-driven scheduling, Project adjusts the work values. If a task must take a specified amount of time, and if you add another resource to that task, each resource will be assigned less of the total work.

Task type behavior is described in the following table.

In a	If you revise units	If you revise duration	If you revise work
Fixed units task	Duration is recalculated.	Work is recalculated.	Duration is recalculated.
Fixed work task	Duration is recalculated.	Units are recalculated.	Duration is recalculated.
Fixed duration task	Work is recalculated.	Work is recalculated.	Units are recalculated.

Resolution

Reset the duration to its previous value

1. Select the task that you want to change.

2. On the Resource tab, choose Assign Resources.

3. In the Resource Name column, select the resource that you added to the originally assigned resources, and then choose Remove.

Turn off effort-driven scheduling for an individual task

1. Select the task that you want to change.

2. On the Task tab, choose Information.

3. On the Advanced tab, clear the Effort driven check box.

Turn off effort-driven scheduling for all new tasks

1. Choose File > Options > Schedule.

2. Clear the New tasks are effort driven check box.