ABSTRACT
This chapter introduces the subject of critical path network analysis. Network analysis, and particularly the use of arrow diagrams, gave planners a valuable new tool with which they could express the logic of a proposed work plan for their projects. All the activities comprising a project are joined by lines which, unlike the arrows in arrow diagrams, usually represent links with zero duration. The heart of any activity-on-arrow system is the arrow diagram, logic diagram or 'network' itself. Although network diagrams are weak in their ability to set out tasks on a timescale, they have other very significant strengths. When compared with bar charts, critical path networks provide the more powerful notation needed to show all the logical interdependencies between different jobs. The serious student or professional planner should be aware of both arrow and precedence diagrams. Dummy activities do not represent actual work and practically always have zero duration. Every activity is given a unique identification number.
