Remaining Effort and Overload Calculation

Information

• By means of the following example it is explained why individual project calculation and replanning (calculation of all projects) bring about different results with regard to remaining effort and overload.

Initial situation:

• There are two simple projects (both adherent to schedule) which both load the same resource at the same time with 18 hours.
• Only difference: One project has a higher priority (for this purpose see the project names).

• The resource uses the CAP load profile at a maximum load of 7.2 hours a day and is not used by any other project.

Replanning

• First it is calculated how many days are required for these projects.
  • In both projects, with a total duration of 18 hours and a maximum load of 7.2 hours, this would amount to 18 / 7.2, hence 3 days rounded up.
• In the higher prioritized project, now the 18 hours are allocated to these three days until all capacities are utilized by 100% or all hours are planned:

• The same applies to the lower prioritized project.
• Since now, however, there is only free capacity on the third day, only 3.6 hours are planned there first.
  • This leads to the “invisible” intermediate result in date scheduling in which all capacities are fully utilized.

• Now, 18 hours - 3.6 hours = 14.4 hours of remaining effort are left for which no more capacity is available.
  • This remaining effort (14.4 hours / 3 days = 4.8 hours per day) is added to all days, which generates an even overload of 4.8 hours per day.
• The final result after replanning hence looks as follows:

Individual Planning of the Higher Prioritized Project

• Here the status of the higher prioritized project after replanning:

• In date scheduling, the project is completely unloaded internally.
• Then again, all available days are loaded until either the entire remaining load is planned or all capacities are seized by 100%.
  • Since the other project already seizes the first two days by 4.8 hours, 2.4 hours each can be loaded here.
  • On the third day, the resource is already overloaded by the other project by 100%, so that there is no capacity left.
• This results in the following “invisible” intermediate result in which all capacities are completely utilized:

• Now 18 hours - 2.4 hours - 2.4 hours = 13.2 hours of remaining effort remain, for which no more capacity is available.
• This remaining effort (13.2 hours / 3 days = 4.4 hours per day) is added to all days, which generates an even overload of 4.4 hours per day.
• The final result after individual calculation hence looks as follows:

Conclusion

• As you can take from this example, both the remaining effort and the overload may change in the individual calculation of a project, even if no changes have been made to the data in the system otherwise.
  • In this case, an overload which is generally to high is displayed distributed over both projects.
    • This occurs because in the individual calculation of a project the scheduling can only determine that resources are reserved, but it cannot determine by which other projects they are reserved.
    • Since the priority of the existing load is unknown (and since the overload of the other projects cannot be calculated anew), it is always presumed that already existing loads are prioritized higher and new loads are added to them - which again leads to the effect described above.