Elements of Time Management

Relationships between activities are easier to recognize if they are presented using graphics such as bar charts or a network of connected boxes.

Bar Charts

The type of bar chart used to illustrate activity relationships in a project is the Gantt chart. The Gantt chart was developed by Henry Gantt and used on major projects, including building the Hoover Dam and the U.S. interstate highway system. The Gantt chart, also called a bar chart, is a time-scaled graphic that represents each activity with a bar that reflects the duration, start, and finish time, as shown in Figure 8.13 Gantt Chart.

Figure 8.13 Gantt Chart

A Gantt chart is easy to read and provides sufficient information for project team members to plan activities within a short time frame. For many larger projects, a two-week bar chart, extracted from the larger master schedule, provides the information needed for team members and contractors to coordinate activity details. The Gantt chart provides information for simple planning but is limited because a Gantt chart does not illustrate complex relationships well.

Network Diagrams

People recognize relationships and patterns more effectively when they look at diagrams like the one in Figure 8.14 "Project Network Diagram". The precedence diagram method (PDM) is a technique for graphically displaying the logic of the schedule by placing the activities in boxes with arrows between them to show the precedence-successor relationships. The boxes in this type of diagram are called nodes and the arrows indicate finish-start relationships. Compare the diagram in Figure 8.14 "Project Network Diagram" to the outline in Figure 8.9 "Outline of Activities with Predecessors Identified" to see how much easier it is to trace a sequential path from one activity to the next in the precedence diagram. This type of diagram is also called a project network diagram.

Figure 8.14 Project Network Diagram