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Expected finish constraint

19 replies [Last post]
Mon, 2005-10-03 02:46
Yves Trudel
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Hi everyone
I plan to use systematically "expected finish" constraint in the following way and I wonder if one could have any warning or comment on it.
For any activity that starts, I put Actual start, and in the same time I change its Early finish into Expected finish constraint.
Before rescheduling with a new data date, I will put progress on activity.(I uncheck "link percent complete and remaining duration")
When I will reschedule the data date, the remaining duration will decrease according to the difference between first and second DD, and my activity finish date will stay the same unless expected finish falls before the second DD
The result would ideally be that the project finish date would not move when I will reschedule.
For any activity with an Expected finish constaint not completed on the second data date, I will create a filter and correct their revised expected finish date. More drastically, I could even build a Global Change to select all these less than 100% activities and change their new expected finish dates say one week after the revised Data Date.
I hope that using this procedure, I will concentrate more into fine tuning progress and logic instead of "correcting" the project to bring back the project end date where it had to be.
Note that I also plan to erase all expected finish constraints between 2 different Data Dates rescheduling in a way that regular F9 process would not be affected by this constraint.All of that being done tru Global Change procedure.
I apologize for such a long email!
Regards
Yves Trudel


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Replies

Fri, 2005-10-07 10:13
#1
Yves Trudel
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You got me right Sen,
In any event I will be extremely careful using this method, and I hope if any of you tries the same, to get news from you so I can improve my method of planning.
Cheers to all!

Yves
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Wed, 2005-10-05 21:41
#2
Sen Moc
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Alex,

Yves already clarified that the “constraint” was only applied on the activities that “has started”. Refer to post#12, second sentence. By this, he meant that he wanted to maintain the finish dates of the updated task…well, hoping that the finished dates or remaining durations were already confirmed.

Cheers!
Sen
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Wed, 2005-10-05 21:30
#3
Zhang Haixiang
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Yves,

If your project is almost on schedule, the way you use is good. If you have lot of activities delayed,ahead or out of sequence,what you do will give you wrong forecast.
I used this kind of method before but only for some activities as someone mentioned before,e.g. procurement,delivery...(but if i have more information about these activities, i will update them manually)
Anyway,you need to update progress according to what actually happened.
You can use this method,after that remove the constraints,then check your schedule,do some manual update if needed.
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Wed, 2005-10-05 20:45
#4
Alex Wong
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Yves

Let me guess, what you try to do is to maintain the schedule in a fastest way where when the schedule change data date you want the finish date more or less same as before prior to schedule except the updated task.

From what I can see and experienced, during this process, you may lost some of the critical path activity. Ie prior to last update certain activity may be not fall into the CP and if you maintain those date and thinking they are mostly on track then you may miss report the end date. I guess what others are very correct is to avoid using constraint during or after progress update; except some of the critical dates such as milestone, equipment delivery date etc...

Remember there is no short cut comes to updating your schedule.
You have to update all activities in order to see the full picture of the CPM network. Of course some data will not be availiable, then you have to have a educated guess, but still you need to update it all.

HTH

Alex
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Wed, 2005-10-05 12:16
#5
Yves Trudel
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To All
From all of that I swear to you I will not keep those Expected constraints more than: the minute before I reschedule... and the minute after it has been recheduled.
Yves
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Wed, 2005-10-05 12:13
#6
Yves Trudel
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In calculating that estimated value of effort, I deduct the end date of that started activity. The moment after, I push my data date. I hope my mind will not have change in between.
That is the only point I’m trying to validate
...Or as you say, I miss the point!
Regards
Yves
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Wed, 2005-10-05 12:12
#7
Jose Frade
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Hello Yves

I support 100% the ideas here refering that you should avoid the use of constraints.

Even though I can support your idea of expected finish constraint in one case:

After placing the Purchase Order for a certain equipment to be supplied by external contractor.

Assuming that the informations you are getting from the field confirm that the contractual delivery time remains - then i would accept, after the manufacturing phase realy started (actual start) to use the expected finish date.

Meanhwile, periodic updates from the supplier will need to be checked for accuracy and consistency towards the constraint.

Please be aware that P3.1 will update automaticaly the activity during the further updates of the project but when the expected date arrives it places there automaticaly 100% (even though displays an error message concerning that particular activity in the reschedule log.

Best regards
JMFrade
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Wed, 2005-10-05 11:07
#8
Steven Oliver
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I think that you are missing the point of updating your plan. It is not merely to confirm the date you had on your last update, but must be a researched and validated estimate of the amount of effort required to complete a task.
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Wed, 2005-10-05 08:58
#9
Yves Trudel
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I guess Sen has got what I have in mind. The Expected "constraint" in this case is no more than planning the remaining duration of an activity just started. By setting a duration we already "constraint" that activity with a "fixed duration constraint" and we know we will have to correct that duration right after rescheduling. But when using Expected finish constraint, we avoid to recalculate that specific activity.
Again, in almost no case I would use and even accept "hard" constraints.
Thank you all for your comments
YVes
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Wed, 2005-10-05 01:28
#10
Sen Moc
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It seems to me that Yves has found a way to ease the work in updating a schedule. I myself did an updating of schedule and ‘twas pain in the butt rechecking the logics and finish dates after inputting the actual dates especially for those activities that are out of sequence.

What Yves did was to identify those activities that will not anymore be completed as per original plan. In my opinion, temporary constraining some activities for the purpose of updating the schedule is ok.

Just make sure to remove them after the schedule has been finalized and before issuing to the client/project manager.

Cheers!
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Tue, 2005-10-04 11:53
#11
Charleston-Joseph...
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Hi Yves,

Constraint distort the logic.

It is preferable to have a free flowing logic.

Charlie
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Tue, 2005-10-04 11:24
#12
Edgar Ariete
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Yves,

IMHO, I think you can apply constraints on Baseline Plans. Just use it as plain baseline for comparison later on, but on your current (updated) it’s not advisable.
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Tue, 2005-10-04 03:13
#13
Bill Guthrie
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yves

most planners only modify remaining duration to control the finish date. Again A good planner NEVER uses constraints unless a odd situation. Many reasons, one is hard to get a risk analysis program to work on constraints,2, some constraints, hard ones over ride logic.

If a contractor submits me a schedule with constraints in it I will kick it back, and tell him to remove all constraints.

Cheers Bill
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Mon, 2005-10-03 12:50
#14
Yves Trudel
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Yes I use Primavera 3.1
What I am suggesting is really to put these expected finish dates only on activities that have an actual start, meaning that I have a strong reference to foresee their finish dates.
It prevents me to be obliged to bring back their end dates after moving the data date. When you have large quantities of activities to update every week, I still believe that this could ease the planner job.
I hope I will find some supporters!
;-)
Yves
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Mon, 2005-10-03 09:26
#15
Bill Guthrie
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assuming you are using primavera 3.1

bill
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Mon, 2005-10-03 09:26
#16
Bill Guthrie
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Yves

When you put in a Actual start, then forget constrants.
its over ruled.

Actual dates are hard dates, and if you have a actual start date,the end date will be relative to the durations and resources loaded.

You need to rethink your thinking. You should use expected finish constraints or any constraints ONLY WHEN PLANNING. how can you develop a schedule for a plan and use Actual dates ????.
you need to sit back and see what you want to do.
If you are planning, then use constraints very lightly if any. Most firms only allow constraints at the start of a job and the end unless a very odd milestones pops up with no predecessor.( like a ship arriving)
Activities should be driven by logic, all activities should have predicessors and successors. Forget constraints.

Now after you develop your schedule and start the job, you THEN install actual dates. ok

And recommend cloning the schedule as the target schedule after you get it developed and set up your schedule referring to it

Cheers Bill Guthrie
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Mon, 2005-10-03 07:09
#17
Raja Izat Raja Ib...
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Hi again,
Actually, i dont know this is revised schedule or what,
but its seems very tedious works may cause the calculation will give wrong answer(file error) and how about the manhours, budget?. To me instead u do that style of work better u try to find activities can be overlap, can be shorten the duration or double the manhours. I think much proper way.
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Mon, 2005-10-03 06:44
#18
Yves Trudel
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That seems fine with me, but I’m looking for comments about the method I plan to use. Is it something that would create more problems than solutions?
Yves
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Mon, 2005-10-03 03:27
#19
Raja Izat Raja Ib...
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try this equation :
IF _ PCT _ LT_ 100 > then (SELECT CONTRAINT)EQ (CLENDAR)
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