There are several reasons to avoid the use of the traditional Activity on Arrow computations and the Non-Continuous PDM (its PDM equivalent).
First and obvious reason is that by an overwhelming preference the Activity on Arrow representation is not used because of the complications the need for the Dummy Activity creates. In complex projects this burden can be overwhelming. This drawback is not existent under the Non-Continuous PDM version but the following statements still apply to both representations.
Second because it provides the dates for the nodes and not the activity, therefore it assumes the activity to be discontinuous with one end driven by the first node and the last end driven by the last node. In the majority of scheduling need the most efficient scheduling of an activity is for it to be continuous. The method denies the scheduler for the use of Continuous scheduling while by merely splitting the activity the Continuous method do allows for the proper application of the splits.
Third, if you need for an activity to be discontinuous this assumption should not be automated as the splitting rule must be determined on a per activity basis, and then there is no benefit on the automation of a rule that must be on a case by case. In addition the splits do have a particular duration of their own, early start and early finish of their own, float of their own which can be different after resource leveling. Because the software summarizes this under a single activity line this information is hidden to the user.
First and obvious reason is that by an overwhelming preference the Activity on Arrow representation is not used because of the complications the need for the Dummy Activity creates. In complex projects this burden can be overwhelming. This drawback is not existent under the Non-Continuous PDM version but the following statements still apply to both representations.
Second because it provides the dates for the nodes and not the activity, therefore it assumes the activity to be discontinuous with one end driven by the first node and the last end driven by the last node. In the majority of scheduling need the most efficient scheduling of an activity is for it to be continuous. The method denies the scheduler for the use of Continuous scheduling while by merely splitting the activity the Continuous method do allows for the proper application of the splits.
Third, if you need for an activity to be discontinuous this assumption should not be automated as the splitting rule must be determined on a per activity basis, and then there is no benefit on the automation of a rule that must be on a case by case. In addition the splits do have a particular duration of their own, early start and early finish of their own, float of their own which can be different after resource leveling. Because the software summarizes this under a single activity line this information is hidden to the user.