Comprehensive appearance
The PNA presents a better appearance than
CPM. In PNA, activities are generally arranged in rows of symmetrically placed
horizontal boxes connected with dependency lines, whereas CPM contains arrows,
dummy arrows and events drawn in forward direction at various angles.
PNA is simpler. It does not contain
dummies, events or unnecessary low order activities. This reduces chances of
error, size of network and the data processing effort.
Colour code, if used for activity boxes in
PNA enables easy identification of critical and non-critical activities.
Different colour codes on these boxes can also represent responsibilities and
resources.
In PNA each activity box includes relevant
data for time and, possibly, resources needed for analysis, but in CPM it is
distributed on arrows and connecting events.
Ease of drawing
The logic-arrow diagram of CPM is easy to
draw whereas PNA takes more time to develop its logic sketch. After
finalization of logic diagram, PNA is quicker to draw than CPM.
Realistic logic representation
PNA takes into consideration overlapping
of activities. These overlapped activities present a realistic sequence of
engineering tasks as they occur in actual execution. PNA can represent four
types of logic, namely, finish-to-start, start-to-start, start-to-finish and
finish-to-finish. These cover real life situations better than the CPM's single
finish-to-start relationship approach.
Ease of logic alteration
PNA enables easy alteration as it involves
connecting dependency lines instead of shifting of arrows and events as in the
CPM network.
Ease of understanding and communication
The CPM network with its distinct events
and simple logic relationship can be easily understood by those not familiar
with network analysis. This is difficult in the case of PNA with its multiple
logic relationship.
Computerization of network
CPM having single logic relationship of
finish-to-start generally, needs less input data than PNA with its multi-logic
approach. However, for a network of the same project, PNA has less activity
input as there are no dummies.
PNA networks can be zoomed in various
sizes and levels on computer screen according to the information needs of
various levels of management. The detailed activity networks can be easily
transformed to the summarized versions.
Manual analysis of network
CPM is comparatively easier to analyze
than PNA. In case of PNA, all the time data has to be transferred from one
activity to its adjoining activity before the adjoining activity can be
analyzed.
Activity label
In PNA, each activity is given a unique
label number. This label can also be used to indicate the activity resources,
whereas in CPM, the label of activity changes with alteration of logic or
addition of new activities.
Time scale network schedule
The schedule derived from CPM can be drawn
both in bar charts as well as the 'time scale network' format in which each
activity is drawn to time scale. The 'time scale network' schedule is difficult
(but possible) in PNA as distortion of activity boxes can result in confusion.