Theory of Constraints Handbook - James Cox Iii [23]
The investigations into the planning, scheduling, and control functions of multiple projects have found several fundamental characteristics inherent in multiple projects:
1. Multiple projects are interdependent due to the use of common resources.
2. Some method must be used to prioritize the use of resources among multiple projects.
3. There is some trade-off between the utilization of resources and the on-time completion of individual projects.
4. Whether organizational or tactical, a control mechanism must exist to reduce the variance between planned and actual project completion dates.
Development of Guidelines
The widespread use of project management techniques and the general failure of projects to meet time, budget, or specification targets beg the examination of the fundamentals of project planning, scheduling, and control from a systems perspective. In the ensuing section, 12 guidelines for project planning, scheduling, and control based on this systems perspective are developed. These guidelines are posed as a starting point in the development of a comprehensive solution to project planning, scheduling, and control. Without this systems perspective of focusing on core problems of project failures, a proposed solution (such as better communications) may create more problems (such as having more project meetings and producing more reports) than it solves. The 12 guidelines are listed in the shaded box and are further explained in the text that follows.
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Guideline I: Recognize the differences between due-date projects and money-making projects. The network structure may be the same, but a project to make money is started as soon as possible (to make money) and a project that is due by a given date is started as late as possible (to save money) while still providing protection for its completion. The project must be viewed as part of the larger system—what are the goal and objectives of the project with respect to the organization’s goal and objectives?
Guideline II: Recognize all of the activities required to achieve the goal of a project and the organization. In application, the goal of the project is generally a milestone in a much larger system. Ensure that the project scope fully defines the activities necessary to achieve the project goal and is in line with the system (organization) goal.
Guideline III: Recognize that 100-percent resource utilization may be counter to the objectives of the project and the organization goal. Plan resource use within and across projects such that the project is completed on time, on budget, and to full specifications.
Guideline IV: The rules for constructing project activity times must be known and practiced by all resources, resource managers, and project managers. A.5 probability of completion for the activities and project is required to determine a correct network. Padding (or buffering) should be applied strategically at the project level.
Guideline V: Minimize the amount of multitasking by critical resources and the amount of multitasking on activities on the critical path of the project to reduce activity lateness. Use multitasking cautiously—understanding its impact on project completion. Strategically buffer non-critical paths, resource contention, and project completions to reduce the impact of Murphy’s Law (Murphy).
Guideline VI: Develop and implement a methodology for prioritizing resource allocation within a project and across projects so that resources know what is most important from the organizational (system) perspective.
Guideline VII: The project manager must consider all activities and dependencies to be completed to achieve the project goals, as well as all conditions that must be met before an activity can begin when developing the project network.
Guideline