Splitting and merging tasks and allocations

You can split tasks into two or more separate tasks, and merge tasks into one single task. Splitting tasks may be useful where you have one activity that you want to divide into a number of activities, possibly with a time gap between them.

You can also split and merge allocations - either permanent resource allocations, consumable resource allocations or cost allocations. Splitting allocations may be useful if you have initially planned a task to have a single allocation, but it then becomes apparent that the task requires two or more different allocations of the same resource or cost centre - with the second allocation perhaps being modelled in a different way to the first, or costing more than the first, or with a gap between the first and second allocations.

You can choose to split tasks in the following ways:

  • In half.
  • At each point on the task at which a link enters or leaves it.
  • At a specified duration.
  • At a specified percentage of the duration.
  • At a specific date and time.

You can choose to split allocations in the following ways:

  • In half.
  • At a specified duration.
  • At a specified amount of effort, work, quantity or cost - depending on the type of allocation and the way in which it is modelled.
  • At a specified percentage of the duration.
  • At a specific date and time.

When you split a task or allocation, the task or allocation is divided into two separate tasks or allocations on the same bar (if you split a task at each point at which a link enters or leaves it, this can result in more than two separate tasks). The resulting tasks or allocations retain the properties of the initial task or allocation, but you can subsequently edit each task or allocation individually.

If a task has one or more task activities, the task activities remain on the original task, but are not copied to the new tasks that are created.

If you split a nonlinear allocation, the resulting allocations are both linear.

Note that you cannot split non-modelled allocations. This is because their duration is set by the duration of the task to which they are assigned, so splitting a non-modelled allocation would result in two identical allocations, each having a duration matching that of the task.

  1. Right-click the task or allocation that you want to split.
  2. Select Split/Join from the popup menu that appears.
  3. Select Split in Half.
  1. Right-click the task that you want to split.
  2. Select Split/Join from the popup menu that appears.
  3. Select Split at Links.
  1. Right-click the task or allocation that you want to split.
  2. Select Split/Join from the popup menu that appears.
  3. Select Split. Either the Split Task dialog or the Split Allocation dialog appears, depending on whether you are splitting a task or an allocation.
  4. Click the Split by duration radio button.
  5. Enter the duration at which you want the task or allocation to be split, for example 3w or 4h, in the field to the right. For example, if you split a 10 day task at 2 days, the task is divided into a 2 day task and an 8 day task.
  6. Click OK.
  1. Right-click the allocation that you want to split.
  2. Select Split/Join from the popup menu that appears.
  3. Select Split. The Split Allocation dialog appears.
  4. Click the Split by effort/work/quantity/cost radio button (the type of allocation and the way in which it is modelled determines which field is displayed on the dialog).
  5. Enter the amount of effort, work, quantity or cost at which you want the allocation to be split in the field to the right. For example, if you split an allocation with 20 units of quantity at 5 days, the allocation is divided into two allocations: one with 5 units of quantity and the other with 15 units of quantity.
  6. Click OK.
  1. Right-click the task or allocation that you want to split.
  2. Select Split/Join from the popup menu that appears.
  3. Select Split. Either the Split Task dialog or the Split Allocation dialog appears, depending on whether you are splitting a task or an allocation.
  4. Click the Split by percentage radio button.
  5. Enter the percentage of the duration at which you want the task or allocation to be split, for example 20 or 75, in the field to the right. For example, if you split a 10 day task at 30%, the task is divided into a 3 day task and a 7 day task.
  6. Click OK.
  1. Right-click the task or allocation that you want to split.
  2. Select Split/Join from the popup menu that appears.
  3. Select Split. Either the Split Task dialog or the Split Allocation dialog appears, depending on whether you are splitting a task or an allocation.
  4. Click the Split at date radio button.
  5. Enter the precise date and time at which you want the task or allocation to be split in the field to the right.
  6. Click OK.

You can merge tasks on the same bar into one single task. You can only merge tasks that are positioned next to each other on the same bar: you cannot merge two tasks if they are separated by a task in between them.

If a task has more than one allocation of the same resource or cost centre - and if the modelling parameters or cost rates on the allocations are the same - you can merge the allocations into one single allocation.

When you merge tasks, the tasks are joined into one single task. The resulting task retains the properties - including any codes and task activities - and name of the leftmost task that you are merging. Any resources or costs that were allocated to any of the tasks you are merging are allocated to the resulting task.

In the simplest case, the duration of the resulting task is the sum of the initial tasks. For example, in the illustration below, 1 day, 2 day and 4 day tasks are merged into a 7 day task:

Three tasks on the same bar

Three tasks merged into one

Before the merge

After the merge

If resources have been assigned to the tasks, all resource allocations are applied to the resulting task. The duration of the resulting task depends on whether or not the resource allocations are allowed to be shorter than the task to which they are assigned. If the resources can be shorter than their tasks, the duration of the resulting task is the sum of the initial tasks:

Two different resources are assigned to the tasks

The tasks are merged into one; the duration is the sum of the original durations

Before the merge

After the merge

If the resources cannot be shorter than their tasks, the duration of the resulting task is equal to the duration of the longest resource allocation:

Two different resources are assigned to the tasks

The tasks are merged into one; the duration is that of the longest resource allocation

Before the merge

After the merge

If you merge a number of allocations into a single allocation and one or more of the allocations is nonlinear, the resulting allocation is linear, unless a resource curve has been applied to the leftmost allocation, in which case the same resource curve is applied to the resulting allocation.

To merge tasks or allocations together:

  1. Select the tasks or allocations that you want to merge:
  2. Right-click one of the tasks or allocations.
  3. Select Split/Join from the popup menu that appears.
  4. Select Join.

The tasks or allocations are merged into a single task or allocation.

Related Topics:

Working with allocations that are shorter than the task

Working with nonlinear allocations and resource curves

Breaking down tasks into smaller steps using task activities