MSP: Microsoft Project Manual Calculation Mode

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Manual calculation affects the schedule in Microsoft Project (MSP). The 
Calculation
 option is 
On
 by default. As a result, when you open a 
Clarity PPM
 project in Microsoft Project, the project is recalculated. The
 
task start and finish dates are automatically adjusted to respect the dependency chain between them.
For example, create two tasks, Task 1 and Task 2, with a Finish/Start dependency between them. The start date of Task 2 is calculated relative to the finish date of Task 1 based on the dependency link. The Gantt chart is also updated accordingly. The subsequent tasks are calculated similarly summing up the task level values for Remaining Work, Actual Work, and Work at the Summary Task level.
 
 
Configure Manual Calculation
You can set the 
Calculation
 option in Microsoft Project to 
Off 
(manual). In manual calculation mode, a 
Clarity PPM
 project is not recalculated when you open it in Microsoft Project. When you use manual calculation mode, Microsoft Project performs in the following ways:
  • Tasks are not adjusted or updated based on the dependency chain when you open a 
    Clarity PPM
     project in Microsoft Project. The dependency chain becomes meaningless.
  • Tasks remain stationary on the Gantt chart.
  • You must schedule a project manually and must shift the task dates.
  • The project appears as it was last saved in 
    Clarity PPM
    , provided you are not using 
    Clarity PPM
     timesheets.
  • The summary task is not calculated. The rolled up values of the child tasks are not displayed. As a result, the project level 
    % Complete
     field in Microsoft Project may display an inaccurate value.
 For MPP projects (
filename.mpp
) that were created before configuring this setting, the project manager must update the global setting for that project.
To update the global setting, open the plan in Microsoft Project from 
Clarity PPM
.
 
Follow these steps:
 
  1. In Microsoft Project, click 
    File
    Project Options
    , and then click 
    Schedule
    .
  2. Select 
    Off
     for 
    Calculate Project after each edit
     in the 
    Calculation
     section.
  3. Click 
    OK
    .
     This setting is global and is saved in the .mpp file of each project. Any .mpp project that is created after configuring this setting inherits this setting.
  4. In 
    Clarity PPM
    , click 
    Administration
    Project Management
    Settings
    .
  5. Set the 
    Default Load Pattern
     as 
    Uniform
    .
  6. Click 
    Save
    .
Example: No Calculation (0 Hours) for Remaining Work 
As illustrated in the following image, the remaining work for Project 1 and Summary is not calculated and displays zero hours. The project is not calculated when manual calculation is enabled.
 
Image illustrating the effects of manual calculation.
 
Press F9 or use the 
Calculation Needed
 button in Microsoft Project to calculate the project. Microsoft Project calculates the plan and the rolled up values of all the tasks are displayed. In addition, the tasks appear on the Gantt chart based on the Finish/Start dependency relationships.
Example: Tasks Remain Stationary on the Gantt Chart
When you enable manual calculation, tasks remain stationary on the Gantt chart and hours do not roll up to the summary task or project levels. For example, enable manual calculation in Microsoft Project and also set the loading pattern to uniform in 
Clarity PPM
. You then create a project in 
Clarity PPM
 with three tasks. Create a summary task and demote tasks as children under the summary task. Apply Finish/Start dependencies and identify remaining work and record actual work.
Open the 
Clarity PPM
 project in Microsoft Project. Because manual calculation is enabled, the project is not calculated and the results appear as shown in the following image:
  • The three tasks are stacked upon each other in the Gantt chart and do not appear based on the Finish/Start dependency links.
  • The summary task displays zero for remaining work, actual work, and work instead of the sum of the tasks.
  • The project can display incorrect values at the project or summary task levels.
 
Image illustrating the effect of setting calculation to manual.
 
Press F9 to calculate the project. The results appear as shown in the following image:
  • The three tasks are scheduled based on the dependency chain between them.
  • The remaining work, actual work, and work for the summary task display the sum of the child tasks.
 
Image illustrating the effect of setting calculation to manual.
 
Example: Summary Task Is Not Automatically Calculated
When you enable manual calculation, the summary task dates are not automatically calculated. For example, enable manual calculation in Microsoft Project and also set the loading pattern to uniform in 
Clarity PPM
. You then create a project in 
Clarity PPM
 with some tasks without dependencies. Create a summary task and demote tasks as children under the summary task. Drag the tasks manually on the Gantt chart to reflect the requirements of the project manager.
Open the 
Clarity PPM
 project in Microsoft Project. Because manual calculation is enabled, the project is not calculated and the results appear as shown in the following image:
  • In the Gantt chart, the Gantt line for the summary task reflects only one day instead of the range of the child tasks.
 
Image illustrating the effect of setting calculation to manual.
 
Press F9 to calculate the project. The results appear as shown in the following image:
  • The Gantt line for the summary task displays the date range of the child tasks.
  • The summary task displays the rolled-up values.
 
Image illustrating the effect of setting calculation to manual.
 
Microsoft Project Manual Calculation Exceptions
The following exceptions apply when manual calculation is enabled:
  •  
    Clarity PPM
     timesheets. If you use timesheets, the actual hours that are recorded against tasks could override the configuration. The start date, finish date, or both can change.
    For example, Task 1 starts on May 1 and Ken records eight hours on April 20, a date before the task starts. The next time that the project is opened in Microsoft Project, the start date of the task changes to April 20. The same is true if Ken records actual hours against the task after its finish date. Microsoft Project moves the finish date to the last recorded actual hours.
  • Resource leveling. Resource leveling calculates the project. Do not use resource leveling if you do not want Microsoft Project to calculate your project.
  • Task constraints. Applying task constraints can trigger Microsoft Project to calculate the project even though the global setting for the Calculation option is set to Off.
Example: Resource Leveling in Microsoft Project
 
Resource leveling
 in Microsoft Project schedules the project based on the availability of the team members so that no resource is overallocated. Resource leveling delays tasks, splits tasks, and delays resource assignments to adjust the resource allocation. Resource leveling also calculates the project as it resource levels. Therefore, level the resources only if you want Microsoft Project to calculate your project.
 
Follow these steps:
 
  1. Set the Calculation option in Microsoft Project to Off.
  2. Create two tasks, Task1 and Task2.
    Microsoft Project automatically sets the start date for both the tasks to be today or the start date of the project depending on your Microsoft Project configuration.
    The tasks remain stacked one upon the other indicating that the plan must be calculated, as shown in the following image:
     
    Image illustrating that the tasks remain stacked one upon the other.
     
  3. Assign the same resource to each task.
    The tasks remain stacked one upon the other indicating that the plan must be calculated. As shown in the following image, the resource is expected to work 16 hours that day.
    Image illustrating that the resource is expected to work 16 hours that day.
     
  4. Manually level the resources.
    As shown in the following image, Microsoft Project automatically calculates or schedules the tasks so that the resource works eight hours a day of availability and therefore resolves the overallocation. If you do not want the task positions to move, do not resource level.
    Image illustrating that Microsoft Project automatically calculates or schedules the tasks.
     
Example: Task Constraints
When you apply task constraints, automatic calculation can be triggered even if the global setting is manual.
 
Follow these steps:
 
  1. Set the Calculation option in Microsoft Project to Off.
  2. Create a task, Task 1.
    Microsoft Project automatically sets the start date to be today or the start date of the project depending on your Microsoft Project configuration.
  3. Move Task 1 to next Monday.
    Microsoft Project marks Task 1 with a 
    Start No Earlier
     constraint. Hover over the Calendar icon to see this constraint.
  4. Create another task, Task 2.
    Microsoft Project automatically sets the start date to be today or the start date of the project depending on your Microsoft Project configuration.
  5. Move Task 2 to next Monday.
    Microsoft Project marks Task 2 with a 
    Start No Earlier
     constraint. Hover over the Calendar icon to see this constraint.
  6. Create a Finish/Start dependency between Task 1 and Task 2.
    When you create task constraints, Microsoft Project automatically calculates the tasks, as shown in the following image, even though the global setting for the Calculation option is set to Off.
    Image illustrating how applying task constraints could trigger an automatic calculate.
     
Example: Reconciling Resource Overallocation
The following example shows how reconciling resource overallocations manually does not trigger automatic calculation.
 
Follow these steps:
 
  1. Set the Calculation option in Microsoft Project to Off.
  2. Create two tasks, Task1 and Task 2.
    Microsoft Project automatically sets the start date to be today or the start date of the project depending on your Microsoft Project configuration.
  3. Assign a resource to Task1.
  4. Assign the same resource to Task2.
  5. Create a Finish/Start dependency between Task1 and Task2.
    The tasks remain stacked one upon the other, as shown in the following image, indicating that the plan must be calculated.
     
    Image illustrating how manually reconciling resource over-allocations does not trigger automatic calculation.
     
  6. Drag Task 1 into Monday of the next week.
    The task remains frozen on the date you manually set, as shown in the following image, indicating that the plan must be calculated.
     
    Image illustrating how manually reconciling resource over-allocations does not trigger automatic calculation.