The critical path method (CPM) is an algorithm for scheduling a set of project activities. It is an important tool for effective project management.
In OpenERP 7, once the user has installed our new modules, she performs the following steps:
- A list of all activities required to complete the project (typically categorized within a work breakdown structure),
- The time (duration) that each activity will take to complete.
- The dependencies between the activities and,
- Logical end points such as milestones or deliverable items.
Let’s start with this example:
|Phase||Task||id||Duration (hours)||Predecessor||Earliest start||Latest finish|
|Proposal||Evaluate the type of proposal and additional requirements.||A||16||01/01/14|
|Proposal||Create proposal document||B||8||A|
|Proposal||Milestone: Proposal finalized||C||0||B|
|Proposal||Review and approve proposal||D||32||C|
|Proposal||Milestone: Proposal approved||E||0||D|
|Cost analysis||Identify costing elements||F||8||A|
|Cost analyisis||Quantify costs for element A||G||8||F|
|Cost analysis||Quantify costs for element B||H||8||F|
|Cost analysis||Quantify costs for element C||I||8||F|
|Cost analysis||Milestones: Cost analysis delivered||J||0||G,H,I|
|Delivery||Presentation to customer||O||8||N|
|Delivery||Milestone: Customer acceptance||P||0||O||31/01/14|
|Delivery||Release to production environment||Q||8||P|
|Delivery||Invoice to customer||R||8||Q|
|Delivery||Milestone: Customer collections finalized||S||0||R|
See how in OpenERP 7 the tasks can be linked to each other:
CPM calculates the longest path of planned activities to logical end points or to the end of the project, and the earliest and latest that each activity can start and finish without making the project longer. This process determines which activities are “critical” (i.e., on the longest path) and which have “total float” (i.e., can be delayed without making the project longer).