why not add an activity that represents the for some reason ? then you are not guess or trying to remember why that start date has changed. In ALL instances avoid using contsraint dates unless they are contractually listed in the contract.
Let the avtivities and logic dictate the schedule This is called critical path method scheduling anything else is simply a glorified bar chart.
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Submitted by Vladimir Liberzon on Mon, 2017-12-11 23:07
Just imagine that your subcontractor informed you that for some reason they will start to work on September 5 instead of September 1 planned in the baseline. Adding Start No Earlier Than constraint is most natural way to enter this in the project schedule.
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Submitted by Zoltan Palffy on Mon, 2017-12-11 16:08
Vladimir, If projects follow EVMS methodolgy and if the forecast plan has deviated from baseline plan to such an extent that earnings do not make much sense then such an instance could necessiate a baseline change without having an impact to the scope.
By the same token, should the durations on future activities be changed (by virtue of gained effficiencies or prodcut deliveries from contractor) thus impacting start dates of future activities without capturing in a baseline change?
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24 years 8 months
Member for24 years9 months
Submitted by Vladimir Liberzon on Sun, 2017-12-10 09:07
Sam, the criteria of estimating project model are simple:
It shall reflect the real dependencies and constraints,
It shall be full and include everything that shall be considered in project schedule.
Project is live and so current version of the project schedule may have constraints that did not exist or were different in the project baseline. Corrective actions like changes in assigned resource crews may change expected activity durations and this is normal practice.
Project baseline shall be changed only if project scope was changed.
I have changed relationships in the forecast P6 file on near term activities which would have impacted start dates of downstream activities in order to align with "current plan" of work being performed. (I may have occassionaly used contraints as well esp in prcurement activites). I feel that is necessary to reflect "reality". The reasonging being there would be minimal impact to resources on account of changes to near term activities (thus not necessiating a baseline change).
I would like to hear your thoughts on if the planned duration of activities in the future have been tweaked to get accurate dates without doing a baseline change.
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24 years 8 months
Member for24 years9 months
Submitted by Vladimir Liberzon on Sat, 2017-12-09 08:40
The only time it is 'desirable' to change the forecast start date of an activity during a status update is if an unadjusted date after the progress information has been entered is logically incorrect. Reasonable logical changes may reflect physical constraints not adequately included in the schedule (eg, issues around safe working and clear access), or resource limitations (eg, a crawler crane being required to be in two different places at the same time, or one work crew being required to work on 30 different activities on the same day). Any adjustment should be incorporated by adding logic or editing deficient logic. The reason for these logical changes need to be recorded. Constraints (ie, imposed dates) should never be used for this purpose.
This is the difference between statusing (adding and processing progress information) and then updating the statused schedule to produce a sensible plan for the work going forward. Some software will assist with this by implementing a 'retain logic' option but you cannot rely on automatic processes to apply common sense. For more on this see: https://mosaicprojects.com.au/Resources_Papers_002.html
Member for
16 years 3 monthswhy not add an activity that
why not add an activity that represents the for some reason ? then you are not guess or trying to remember why that start date has changed. In ALL instances avoid using contsraint dates unless they are contractually listed in the contract.
Let the avtivities and logic dictate the schedule This is called critical path method scheduling anything else is simply a glorified bar chart.
Member for
24 years 8 monthsJust imagine that your
Just imagine that your subcontractor informed you that for some reason they will start to work on September 5 instead of September 1 planned in the baseline. Adding Start No Earlier Than constraint is most natural way to enter this in the project schedule.
Member for
16 years 3 monthsno constrints are typically
no constrints are typically not used for updating it is better to revise the logi and or duration so that it reflects reality
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19 years 4 monthsVladimir, If projects follow
Vladimir, If projects follow EVMS methodolgy and if the forecast plan has deviated from baseline plan to such an extent that earnings do not make much sense then such an instance could necessiate a baseline change without having an impact to the scope.
By the same token, should the durations on future activities be changed (by virtue of gained effficiencies or prodcut deliveries from contractor) thus impacting start dates of future activities without capturing in a baseline change?
Member for
24 years 8 monthsSam, the criteria of
Sam, the criteria of estimating project model are simple:
It shall reflect the real dependencies and constraints,
It shall be full and include everything that shall be considered in project schedule.
Project is live and so current version of the project schedule may have constraints that did not exist or were different in the project baseline. Corrective actions like changes in assigned resource crews may change expected activity durations and this is normal practice.
Project baseline shall be changed only if project scope was changed.
Member for
19 years 4 monthsPatrick / Vladimir, Thanks
Patrick / Vladimir, Thanks for the response.
I have changed relationships in the forecast P6 file on near term activities which would have impacted start dates of downstream activities in order to align with "current plan" of work being performed. (I may have occassionaly used contraints as well esp in prcurement activites). I feel that is necessary to reflect "reality". The reasonging being there would be minimal impact to resources on account of changes to near term activities (thus not necessiating a baseline change).
I would like to hear your thoughts on if the planned duration of activities in the future have been tweaked to get accurate dates without doing a baseline change.
Member for
24 years 8 monthsPatrick, all conflicts that
Patrick, all conflicts that you described shall be solved by resource leveling. Adding artificial dependencies is poor practice.
But if activity start is delayed due to the reasons external to project model it is natural to use the constraint or special activity calendar.
Member for
24 years 9 monthsThe only time it is
The only time it is 'desirable' to change the forecast start date of an activity during a status update is if an unadjusted date after the progress information has been entered is logically incorrect. Reasonable logical changes may reflect physical constraints not adequately included in the schedule (eg, issues around safe working and clear access), or resource limitations (eg, a crawler crane being required to be in two different places at the same time, or one work crew being required to work on 30 different activities on the same day). Any adjustment should be incorporated by adding logic or editing deficient logic. The reason for these logical changes need to be recorded. Constraints (ie, imposed dates) should never be used for this purpose.
This is the difference between statusing (adding and processing progress information) and then updating the statused schedule to produce a sensible plan for the work going forward. Some software will assist with this by implementing a 'retain logic' option but you cannot rely on automatic processes to apply common sense. For more on this see: https://mosaicprojects.com.au/Resources_Papers_002.html