Trace driving activities

Aryan,



In such case, to filter only those activities that will cause the delay to the project, Mikes answer is the direct solution, just apply the filter for critical activities, true if:



a) When using multiple calendars you select for your critical path equal to longest path.

b) You are not using resource constraining, i.e. leveling or smoothing.



There is an erroneous perception that critical path activities as defined in traditional CPM computations are the only driving activities that will affect your total project duration, this is not always the case, so keep it in mind when resource leveling your schedule.



The following is a very simple schedule showing the effect of resource leveling on the traditional critical path computations. Before resource leveling all activities are driven by logic, after resource leveling your job duration is driven by resource availability, traditional critical path is no longer continuous and the first activity even shows some float. Traditional critical path is not identifying the driving activities.







Best regards,

Rafael

Mike



A driving predecessor might even be the predecessor with the most amount of float.



In the following example the driving predecessor of activity 1010 is 1000 with a total float of 7 days and not 1040 an activity on the critical path with a total float of 0.



Trace driving relationships



Best regards,

Rafael

Hi Rafael



Finding driving activities the way you describe it only works if there is a bottom up FS network.



If there are 10 predecessors to an activity such as - "Whole Project Test & Comission" then the one with the least float would be the nearest to a driving activity.



Not dificult to filter out through the upstream chain.



It wont work with top down SS lead lags.



Best regards



Mike Testro

Mike



The start of all activities is driven by the start of job or another activity, even when not in the critical path, this applies to all activities.



A non critical activity might have 10 predecessors, which is the driving predecessor is of concern, especially when having not much float (a near critical activity). Knowing driving activities is relevant to avoid delaying near critical activities into the critical path.



You identify driving activities through driving relationships.



Remember Monte Carlo, at times duration of near critical activities varies more than those in the critical path. Then these activities drive the project duration even further than the variations on the original critical path. Critical path is so blindingly obvious that the original PERT computations were wrong when missed the near critical activities.



Aryan



Although at times I can live without using trace logic and PERT diagrams it is important you know them, especially when logic is on more than 2 levels, is almost impossible for your clients to communicate logic with prose as if a Shakespeare poem.



My clients communicate logic with such diagrams written by hand then I insert them into the CPM. It is said that 90% of CPM is when you develop the model logic. How can you communicate the logic with others without such diagrams, by prose? Your question on tracing logic goes directly to the 90% of what scheduling is all about. You got to review and validate your logic at the very beginning.



Best regards,

Rafael

Hi Aryan



Am I missing something that is so blindingly obvious.



A properly constructed programme will have a critical path.



Nearly every type of planning software will show this critical path in a bright red colour.



Some will allow you to filter out those activities.



So what is your problem.



Best regards



Mike Testro

You got to explore all as some are better suited for debugging while others are better suited for reporting.



Best regards,

Rafael

You can use the predecessor, successor or relationship tabs in Activity Details to identify driving relationships and use the go-to button to move.



You can use trace logic; Click the Layout Options bar and choose Show on Bottom, Trace Logic. In the Gantt Chart or Activity Network upper layout, select the activity from which you want to begin tracing logic. To move through the chain of activities, click a predecessor or successor of the selected activity.



In SureTrak you can filter for driving relationships when in a layout view organized by successors or predecessors, maybe you can mimic this in P6.



Under Powerproject you can toggle off and on the display of non-driving relationships in the bar chart view.

Best regards,

Rafael