80/20 rule: Nguyên tắc Perato
8/80 rule: Nguyên tắc đặt độ dài tối thiểu của work package là 8h và tối đa là 80h 100% rule: WBS phải cover được 100% lượng phạm vi của dự án.
The Pareto principle (also known as the 80–20 rule, the law of the vital few, and the principle of factor sparsity) states that, for many events, roughly 80% of the effects come from 20% of the causes
The 8/80 Rule says that no work package should be less than 8 hours or greater than 80 hours. Notice we said that the work package is the lowest level of the WBS. Activities and tasks are not included in the WBS.
The 100% rule states that the WBS includes 100% of the work defined by the project scope and captures all deliverables – internal, external, interim – in terms of the work to be completed, including project management.
The 100% rule is one of the most important principles guiding the development, decomposition and evaluation of the WBS. The rule applies at all levels within the hierarchy: the sum of the work at the “child” level must equal 100% of the work represented by the “parent” and the WBS should not include any work that falls outside the actual scope of the project, that is, it cannot include more than 100% of the work… It is important to remember that the 100% rule also applies to the activity level. The work represented by the activities in each work package must add up to 100% of the work necessary to complete the work package.