Multiple Project CCPM

The TOC process applies directly to manage projects in the multi-project environment. Consider the multiproject system illustrated by Figure 8.1-9. Resources share their time across the three projects,

Figure 8.1-8 Tracking Project Progress with a Fever Chart to Signal the Project Team When to Take Action to Recover Buffer

Weekly Buffer History As Of 2/15/2002 9:41:07 AM Project: Puma_Ver_01 Milestone: Project End

100%

100%

Longest Chain Complete
Figure 8.1-9 A Multiproject Plan with Resources Allocated One-Third to Each Project

10 11 12

Activity 3 Activity 4 Activity 5 Activity 1 Activity 2 Activity 3

Activity 5 Activity 1 Activity 2 Activity 3 Activity 4 Activity 5

45 days

45 days 45 days 45 days 45 days 45 days 45 days

45 days 45 days 45 days 45 days 45 days 45 days

n'98

Feb "98

Mar'98 ¡Apr'98 lMav'98 |jun'98 IjuI'98 I Aug'98 |sep.g8

4 I11H8I25

I— t— t—

9 5 12 19 21

3 10 17 24

31 7 U 21

1 5 4

12 19 26

2 | 9 116 23

0 I 6 113 120

which causes all project tasks to take more than three times as long as they need to. Multiproject CCPM identifies the multiproject constraint as the most used resource across all of the projects and staggers the projects so resources can work 100 percent on any task they are assigned to, like the runners in a relay race. The projects are pipelined so the resources can move from project task to project task as needed to make the whole system of projects flow to the capacity of the constraint resource.

The management team first has to identify the company capacity constraint resource. This is most often a certain type of person, but may be a physical or even a policy constraint. The company constraint resource becomes the drum for scheduling multiple projects. This terminology comes from the TOC production methodology, where the drum sets the beat for the entire factory. Here, the drum set the beat for all of the company projects. Think of the drummer on a galleon. What happens if even one rower gets out of beat?

The project system becomes a pull system because the drum schedule determines the sequencing of projects. Management pulls projects forward in time if the drum completes project work early. Delays could affect subsequent projects when the drum is late. For this reason, projects in a multiproject environment also require buffers to protect the drum to ensure that they never starve the capacity constraint for work. CCPM schedules the projects to ensure that they are ready to use the drum resource should it become available early. CCPM staggers projects to the capacity of the drum resource, so resources can focus on one task at a time and all projects can finish sooner (see Figure 8.1-10).

Note that CCPM does not attempt to schedule all resources across all projects. The reason is that such schedules change every

Figure 8.1-10 Staggering Projects to the Capacity of the Drum Resource

Figure 8.1-10 Staggering Projects to the Capacity of the Drum Resource

day as the project tasks vary. The schedule can never provide task-level start and stop dates. It is essential to determine the right task to work on based on the actual results to date. Thus, attempting to schedule into the future for all resources is meaningless. Dynamically answering the question, "Which task to work on next?" also makes it unnecessary.

Also note that synchronizing the projects to a single drum resource reduces resource contention for all resources, not just the drum resource. The example actually eliminated contention between resources for all projects because the projects are identical. Although most multiproject environments do not have identical projects, synchronizing projects to the drum usually reduces a significant amount of the resource contention in the plans, even if it does not eliminate all apparent cross-project resource contention.

The reason there will be sufficient capacity for all resources with this approach is that the drum resource is the most loaded resource across all of the projects. Leveling across projects for the most loaded resource allows sufficient time for the other resources, which have excess overall capacity, to complete their work. This does not prevent actual conflicts for any of the resources, including the drum resource. It simply ensures that there is enough time to resolve those conflicts and keep to the scheduled completion date. Buffer status provides a tool to decide which task to work on next, resolving the conflict for the resources. When they have more than one task available to work, they work on the one causing the most project buffer penetration.

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