Critical activities are one of the key terms in Critical Path Method (CPM) or Critical Path Analysis (CPA). Critical Path Method is a network based method for scheduling projects. All critical activities that have direct impact on project end date are gathered into Critical Path.
Critical Path Method was developed by Morgan Walker from E.I. du Pont de Nemours Company and James E. Kelley Jr. from Remington Rand in 1956. It was originally developed to improve functioning of the organization. The first experimental confirmation of the value CPM was made in 1958 when two analytical groups where working simultaneously on the same project. Results achieved by group that used CPM was much better than group with traditional approach.
Let's take into considaration software project that is planned to be deliver in Waterfall approach. We can distinguish the following activities:
|A||Gathering requirements||10 days|
|C||Architectural design||2 days|
|G||Deliver to client||7 days|
|H||Estimate hardware requirements||3 days|
|I||Order hardware||12 days|
Some of the activities must be finished before other can start. There is possibility to find the following paths:
- Gathering requirements (10 days) -> Analysis (5 days) -> Estimate hardware requirements (3 days) -> Order hardware (12 days) -> Deliver to client (7 days) - 37 days
- Gathering requirements (10 days) -> Analysis (5 days) -> Architectural design (2 days) -> Implementation (15 days) -> Documentation (5 days) -> Deliver to client (7 days) - 44 days
- Gathering requirements (10 days) -> Analysis (5 days) -> Architectural design (2 days) -> Implementation (15 days) -> Tests (10 days) -> Deliver to client (7 days) - 49 days
The longest path is third one and that path is called Critical Path. Project will be delivered in approximately 49 days. All steps: gathering requirements, analysis, architectural design, implementation, tests, deliver to client are considered as critical activities. Any delay on those activities will affect final delivery date.
- Bokor O., Hajdu M., (2015), Investigation of critical activities in a network with point-to-point relations, Procedia Engineering
- Hajdu M., Skibniewskib M.J., Vanhouckec M. , Horvathd A. , Brilakise I., (2016), How many types of critical activities exist? A conjecture in need of proof., Procedia Engineering
- Maidamisa A., (2013), Project Management using Critical Path Method (CPM): A Pragmatic Study, Global Journal of Pure and Applied Sciences
- Nafkha R., (2016), The PERT method in estimating project duration, Information Systems in Management
Author: Agata Skalska