Author Question: What is the fundamental difference between an arrow diagram and a precedence diagram? What will ... (Read 59 times)

anshika · **on:** Jul 26, 2018

What is the fundamental difference between an arrow diagram and a precedence diagram?

What will be an ideal response?

Question 2

What is an example of a procurement activity that might be a valuable inclusion in a network? Conversely, what is an example of a procurement activity that has little merit for inclusion in a network?

What will be an ideal response?

xiazhe · **Reply #1 on:** Jul 26, 2018

Answer to Question 1

Arrow diagrams depict activities as arrows while precedence diagrams
depict activities as nodes. Because of the fundamental difference in the methods of
graphically preparing the diagrams, precedence diagrams are generally considered to
be easier to develop and understand. While both types of diagrams depict essentially
the same information, arrow diagrams may be more complex to develop as dummy
activities (artificial activities that consume no time or other resources but are
necessary to show proper relationships between activities) may be required to show
proper logic. There are no dummy activities required in a precedence diagram. Also,
events are automatically included in arrow diagrams, but they must be specifically
added in precedence diagrams.

Answer to Question 2

Major pieces of equipment that are to be incorporated in a project are often
included on schedules. This is especially true of equipment (or materials) that have a
long lead time associated with their fabrication and delivery. Any items that are in
short supply or that cannot be readily obtained should be considered for inclusion in
the procurement activities on a schedule. When materials or equipment are
particularly expensive, their inclusion may also be desirable so that the cash flow
impact can be more fully evaluated.

Examples of procurement activity items that are often included in schedules include
elevators in a multi-story structures, specially-fabricated hoists, electrical switch gear,
custom tiles, large electrical motors, etc. Procurement activities that may not be
warranted for inclusion in the schedule include those related to stock purchases and
small items that might be readily available. For example, the purchase of 16 penny
nails for a small wood frame structure would generally not be included in the network
schedule.