identifying the specific activities that you’ll be scheduling. Once
you’ve done this, you’re ready to create the network diagram.
The network diagramming process begins by defining the
relationships that exist among activities. Some people try to skip
this step and attempt to execute their project directly from an
activity list. This is the “To do list approach.” Although this may
work for extremely small projects (20-30 activities with one or
two people), it will not work on projects that involve dozens of
tasks with multiple players. In most projects, several people are
working on different activities at the same time and many activi-
ties are dependent upon one another, so it’s virtually impossible
to manage a project from a list. A network diagram is required.
The most common graphical convention for drawing net-
work diagrams is the Precedence Diagramming Method (PDM).
PDM diagrams consist of boxes that represent activities. The
relationship between activities is indicated with arrows.
Figure 7-6 indicates that Activity A must be completed
before Activity B can begin. This is an example of a series rela-
tionship,also known as “Finish-to-Start” relationships, for obvi-
ous reasons. Series relationships are by far the most common
type of relationship.
The other type of relationship occurs when two activities can
be done at the same time—aparallel relationship. Figure 7-7
illustrates one way of showing a parallel relationshipin a net-
work diagram. In this example, Activity C and Activity D must
both be completed before Activity E can begin.
Note that no relationship is implied between Activity C and
Activity D, as there’s no arrow connecting them. In some cases,
however, a relationship mayexist between two activities that are
to be done in parallel. This type of relationship will link either
124 Project Management
Activity A Activity BFigure 7-6. PDM series relationship