Activity Networks: PERT (Three-Point Analysis) and CPM
PERT and CPM analysis methods share these basic requirements:

1. All of the individual tasks in a project must be understood well enough to be put into a logical sequence (network) and must have realistic duration estimates.
   
   
2. Critical Path for the whole project (and critical paths for sub-networks in the project) should be determined by analyzing each parallel path in the network.

Both PERT and CPM are network analysis methods used in planning and control. PERT uses statistical analysis to evaluate uncertainties in duration estimates. CPM uses only the “most likely” duration estimate for each task to evaluate critical path in parallel networks. However, both methods can be used to calculate critical path of a project. Again, do not analyze in a vacuum. The team members responsible for each set of activities must develop and understand the dependencies, and how they affect each other’s work. Remember that projects are managed by people, and these methods help the team to understand their mutual dependencies.