Weaknesses

• The precedence relations in the project network are too restricted, allowing activities to start only when the predecessor set is complete. No provision for partial or complete overlapping exists.This has been allowed in Precedence Diagramming Method (PDM) which has four types of lead lag relations: FS, FF, SS and SF
  
  
• There is no provision in the project network to accommodate choices or decisions that may lead to only partial network realization. This has been attempted by Crowston and Thompson in the development of Decision Critical Path Methods (DCPM). This is a good device to display all choices and the consequences and the analysis reveals the set of decisions to optimize total project performance.