Have you ever had a Primavera P6 situation where all predecessors of an activity are 100% complete but the activity’s Start date isn’t pushed to the Data Date as expected? Similarly, you might also see the activity’s Finish date is much later than the it’s remaining duration from Data Date? If you answered yes then this quick tip might help you find the offending activity cause these problems.
THE PROBLEM
To illustrate this problem with out-of-sequence activities in Primavera P6, let’s have a look at this schedule with Data Date of 02-Aug-16.
There are 2 activities with unexpected dates, Dummy Activity 05 and Dummy Activity 06, so let’s investigate further. If I select Dummy Activity 05 and have a look at the predecessors of this activity in the Details Form, it clearly shows that all the predecessors to Dummy Activity 05 are completed, therefore one would expect Dummy Activity 05 to have a Start date of 02-Aug-16 and not 09-Aug-16.
Following same steps, Dummy Activity 06 should have a Finish date of 15-Aug-16 and not 22-Aug-16 since all its predecessors are also completed.
These 2 scenarios normally prompts the question; “Why are the dates not as expected”?
The simple answer is that these activities were executed in an order different than the order we had planned (called out-of-sequence progressing). At the same time, we’re using a scheduling setting in Primavera P6 called Retained Logic. Retained Logic handles how Primavera P6 will schedule progressed activities and in the case where activities are progressed out-of-sequence, P6 will ensure the schedule still retains the original logic between activities.
THE SOLUTION
A way to trace the activity or activities currently driving the dates of Dummy Activity 05 and Dummy Activity 06 is to add 2 fields to the Predecessors section of the Relationships tab of the Details Form: Early Start and Early Finish.
All activities that are 100% complete should have Early Start and Early Finish dates on same date as the Data Date, therefore any completed predecessor with Early Start and/or Early Finish dates other than the Data Date is the offending activity causing Dummy Activity 05 and Dummy Activity 06 to display wrong dates.
From image above, Dummy Activity 04 has Early Start and Early Finish dates of 08-Aug-16 despite been 100% complete, therefore pushing the Start date of Dummy Activity 05 to 09-Aug-16.
If we check Dummy Activity 04, we will notice that its predecessor, Dummy Activity 01, is still in progress with an Early Finish date of 08-Aug-16 and it is this date that has been cascaded to Dummy Activity 05 based on Retained Logic setting.
Now that I have found the offending out-of-sequence activity.
Changing the relationship logic between Dummy Activity 01 (which is still in progress) and Dummy Activity 04 (which is 100% complete) from FS to SS should solve the problem as shown in the figures below.
The Start date of Dummy Activity 05 is now 02-Aug-16 as expected and also the Finish date of Dummy Activity 06 is also now 15-Aug-16 as expected. Similarly the Early Start and Early Finish dates of all the completed predecessors are now 02-Aug-16 as expected.
CONCLUSION
I know that after tracing the out-of-sequence activity, I then changed the relationship type from Finish-to-Start to Start-to-Start. But before you follow suit, it is best you do the following:
- Check that the Project’s planning procedure to see if your specification allows changing of activities relationship logic post-baseline.
- Check with the Project Engineers to find out what the revised relationships for the out-of-sequence activities should be.
Finally, I hope you have found this quick tip useful and as always I would welcome your comments below. What do you think?
Jerome, Brilliant solution. I so rarely use “Early” dates – I either use Start/Finish and frequently Remaining Early Start but it’s an annoying problem sometimes and this is a great way to get to the bottom of it. Like all the best solutions it’s simplicity itself. I’ve been doing this job for a hundred years and still learning!
Thanks Derek,
Glad you found this quick tip useful.
Kind regards,
Jerome
Dear Jerome ,
Can you please prepare the video for this
Tijo,
Unfortunately, I’m not in a position to produce a video tutorial.
Jerome
Fear Jerome,
Usually I just deleted the predecessor when this happen, there 100% anyway it’s a shortcut solution if your are not constrained by the client scheduling requirements.
But this is the way we should fix the error, and I salute you for giving us this tips.
Thank you.
Thanks Joe
=jerome
I work for Consultants and Clients at present – Most of the contracts clearly states that it doesn’t allow such changes to logic (past logic) except in a Revised Baseline Programme.
In the absence of any mention in the contract I have followed the task of identifying and correcting the out-of-sequence relationships in already progressed activities in few of my contracts with strict coordination and agreement with the contractor. I have seen in such cases that the forecast dates are very reliable. The major disadvantage is that such transparency needs to be ensured throughout especially considering the fact that the contractors mostly fail to maintain a log leading to the control over the updated schedule practically spoiled. It can lead to further unnecessary complications when dealing with the Extension of Time claims especially when there are disagreements on the implemented changes to logic.
I suggest to adopt this step if we can maintain logs and the contractor and consultant agrees on the changes as a log each time before such changes actually takes place and the log is communicated, verified and agreed upon – otherwise the normal constraints like ‘Baseline Programme to be maintained as a Bible’ applies. Practically I have noticed that it is not a good decision considering the several instances where the contractor’s planning person makes several changes without logging them.
The practical way of getting out is to estimate precisely when to raise the flag regarding Revised Baseline Programme which is implemented in most projects due to the resistance of the contractor and the existence of claim events. The Revised Programme should be submitted and approved at a fast pace before these out-of-sequence activities exceed an acceptable level and the updated Baseline Programme becomes a useless entity which misleads the whole project and it’s stakeholders.
In projects where the logs were maintained and the contractor was transparent and honest, the results were outstanding and the programme gave realistic dates. The idea is to first verify the programme without the required changes in logic and then do the changes in coordination and agreement after updating the necessary logs. Each time you have to observe the status of the yet to start activities and note that the dates are realistic – if they are not an expert decision has to made on when to raise the flag to go for a Revised and Updated Baseline Programme.
The above is not applicable in projects where the contract allows for a ‘Progress Override’ method while observing out-of-sequence activities. This also has its merits and demerits when it comes to Extension of Time claims which itself is a wider topic to cover here.
Progressing situations with out-of-sequence issues are sticky indeed. If the schedule was progressed in an order that is not represented in the schedule, and a contract or schedule spec states that P6 must stick to Retained Logic, then the recommendation is to adjust the logic of the progressed activities to represent the order that activities were in fact executed. The most important aspect about this is communication about out-of-sequence with the team – a discussion that focuses on how to handle these situations and how to reflect them in the schedule. So discuss first so everyone understands what you’re doing to the schedule. Utimately, the progress schedule should reflect how the work was executed in the field, and a log should be kept with the changes made to the logic. Of course, every project and contract will be different (and likely frustrating).
Greetings to all
I really do not realize how consultant asks for such logs to be kept and recorded, it is either they are super-powerful planners and above the nature or they are really do not know the volume of work required to log such changes.
to be more specific when working in a none typical project that consist of multiple buildings in different locations and multi disciple activities of EPC nature with restrictions on resources such as offshore projects, and a list of activities that exceed 10K, the sequence of work is something that cannot be controlled during the execution specially when the work open front is not released for contractor as planned, if we need to keep logging such stoppage and resubmit the schedule with all backups to get client approval we will end up doing the planning package on every weekly report and never have a constant plan / target.
as a contractor I would agree the schedule with client approval and keep the logic unchanged whatsoever this will serve the project forecast and EOT.
however at a certain stage, the schedule forecast completion date will absolutely become unacceptable, this is when a real change is required by re-visiting the critical path and the remaining works status with respect to uncompleted activities that are driving the critical path, a revised schedule then can be submitted to get the necessary approval but again this is to be done when it is really required.
Riyad,
Appreciate your comment about contractual implication of changing logic but the tutorial is about a quick way to TRACE out of sequence activities when RETAINED LOGIC setting in P6 is in place. Instead of spending minutes trying to find where the problem lies, it is hoped that this method will save time.
I also added a caveat in my conclusion that logic should only be changed if permitted on the project.
Kind regards,
=jerome
Excellent tip and comments!
Thanks Nelson,
=jerome
Very handy tip Jeome. Thanks.
Azeemus
After scheduling, open the log file you will see the out of sequence error (predecessor does not complete while successor completed) and that is the cause to push the finish date of successor out of sequence. And the way I solve is the same with Mr. Jerome Ijachi Odeh proposed, in this case we can break the link and assign new relationship.
Thanks Mr. Jerome Ijachi Odeh,
This is an nice example of Ron Winter’s paper notes about relationships dates in P6. Way to go.
Is it required to document the logic change. Is possible to do progress override instead of retain logic. Please clarify
I have to monitor the Out of Sequence (OOS) activities and get approval for the soft logic changes for the OOS activities during update if required. So that I need more clarity on the OOS as follow;
I wanted to know that how primavera identify the OOS?
How can we categorized the OOS?
How can we filter the OOS activities (not from the log)?
FAZL, Thank You, SIR !!!!!! Excellent P6 Thread. I would also like to add:
I further recommend after following your instructions, for other users to ALSO go to >Edit, >User Preferences, then select 24 Hr, AND check the box for “show minutes”.
(Now Save that layout for purpose of OutofSequence Analysis). You can now more easily see that the (ES or EF) delta from DD (within your Relationships / Predecessors view, typically lower right) …………..is often less than a full day. Sometimes the delta is only a few HOURS !!
*** i meant lower left
Simply log into file and see which activities are out of sequence, correct the sequence if its predecessor is activity and still successor is not completed then you should change the relationship, its simple.Its better to keep the retain logic and not progress override to keep the schedule up to date.
Jerome:
I have one activity that finishes on 5/26/19 but the other activity does not start till 7/11/19. Why is P6 doing this & How do I fix this gap?
2nd question:
Suppose I have 4 lathe machines R4=Lathe (L1, L2,L3, L4) I would like P6 to assign each of these like L1,L2,L3,L4 and then again L1,L2,L3,L4 in this sequence but it does not do that. Is there a way to make P6 do that? and how.
Thanks
Tanvir