Hello

I am struggling with the following tasks dependency problem:

I have:

SUMMARY_TASK
PHASE_1_SUMMARY_TASK
TASK_1a
TASK_1b
PHASE_2_SUMMARY_TASK
TASK_2a
TASK_2b
PHASE_3_SUMMARY_TASK
TASK_3a
TASK_3b

The phases and respective subtasks are supposed to be sequential, i.e. PHASE_1_SUMMARY_TASK has to finish for PHASE_2_SUMMARY_TASK to start etc.

However I have specific dates that the phase 2 should start, which actually might change over time.

So what I want to do is "synchronize" my main "SUMMARY_TASK" based on phase 2.


e.g. if phase 2 date moves ahead in time by 5 days then I would like the tasks of phase 1 and 3 to also be respectively shifted in time.

I have tried to add a task_X which represents my "phase 2 date of interest" and I have linked it with a Start-to-Start dependency" with the "Phase 2 summary task". Picture attached. However what happens now if I move the task_X by 5 days is that phase_2 and phase_3 are shifted in time by 5 days however my phase_1 remains at the same point in time. How can I fix the dependencies so phase_1 also moves?

Hope I explained this clearly..!

Let me know if someone can help!

Regards
Nantia

Attached Images

my_task.png (18.3 KB, 28 views)

I just deleted my first reply, as I think I misunderstood your question

As I understand, you want Phase 2 to start on a fixed date, regardless of when the preceding activities end? Best way to achieve this would be to put a "must start on" constraint on the first task of phase 2. This would lock it in place, regardless ofwhat other phases do. If the start date for phase 2 changes, simply change the constraint date to the new one. This should keep the milestone (Pick up point #1 consistent.
Of course if phase over runs or phase 2 moves back, phase 1 will show a negative float, as it is constrained by Phase 2 (as I see it). However this would highlight less time for phase 1, which would have to be manually adjusted anyway.

Thank you Guloluseus for your prompt reply!
I am afraid I did not explain it very good..
Let me rephrase please.
I have a summary task with 3 phases.
phase 1 --> phase 2 --> phase 3

For my project I can control only when phase 2 starts.

The start date of phase 2, basically defines when phase 1 and 3 need to start. Phase 1 has to finish exactly when phase 2 starts. Phase 3 needs to start exactly when phase 2 ends.

I will probably be asked to change phase 2 start date many times, so I need my planning to be flexible and for phase 1 and 3 to adapt automatically to the changes.

So what I want to illustrate in my Gaant chart is that if i move the start of phase 2 by X days (in the past or the future), I would like both phase 1 and phase 3 to be adapted automatically and be shifted accordingly by X days.

Let me know please if you have advice on how to handle the dependencies for that.

Thank you
dnantia

Ah- I see what you mean now
The project hasnt actually started, and you want phase 1 and 3 to move to suit phase 2?

If thats the case (your explanation is good, I may just be missing the point I'm afraid) then I would tend to change the layout slightly. Instead of using start of phase 2 to set the task 1, use task 1 as a start for phase 2, using a "must start on" constraint. Then link phases 1 and 3 from this date, using a SS relationship with a negative lag.

I have included an mpp and pdf of your project, showing your original layout and my suggested layout. Note that negative lags are generally frowned upon (by convention) but in this case I think it would be the most useful and effective way to show what you need to.

If the start date for phase 2 changes, just change the constraint date in task 1 (the phase 2 start date) and this will automatically change phase 1 and 3. The only thing I wasnt sure of was the lag between phase 1 and phase 2- I used a positive lag in the first example to set these to your days, but you can change this to whatever you want it to be by adjusting the lag to phase 1.

Hope this is helpful- if will check in a day or so in case it doesnt do what you want

NOTE mpp file is zipped, as the board doesnt accept a straight mpp (strange fo ra Project help board, but what the hey )

Attached Files

	HiQ example.pdf (73.6 KB, 11 views)
	HiQ examplempp.zip (27.2 KB, 11 views)

Thank you so much for your detailed answers and mpp! You are very kind!

I think I understand what you are saying, there are some things which concern me with this implementation, let me know what you think please!

The idea is that at the end, this project will have hundreds of summary tasks like the "hiQCZ". Every one of these summary tasks will have a different duration for phase 1, 2 and 3. What I will try to do is "group" together the summary tasks which have for example the same duration for phase 2 and handle them as one set.

Then basically if I manage to fix the dependencies correctly, when I move the "Pick Up date for phase 2" or whatever you want to call it, then the whole group/set of summary tasks will shift to the left or right depending where I shift the date.

So having that said, I am not sure how to define the appropriate lag duration and if this is beneficial for my approach at the end... I would like not to have lags and go for the ideal scenario. Is there maybe a way to do this without lags?

Thank you!

Welcome
Agreed lags are not the best way to do this (as I said before). For an alternative, you could relink phase 1 to phase 2 to phase 3, and then set the constraints on all phase 1 tasks to "as late as possible". This would mean that phase 2 to phase 3 would be a normal dependency (occurring one after the other), while the constraint would push phase 1 to its latest possible start, which would be controlled by the phase 2 date.

Its probably easier to do than to explain, give it a try and see if it gives a better result

Many many thanks for all your help! I ll give it a try!

Hello Guloluseus and happy new year!

I followed your recommendations and I ve placed all my 'phase 1' tasks with constraint "as late as possible" and I am getting slightly better results.

In the attached mpp for example, if I change the start date of my phase 2 task in line 8 for example, then indeed I can see the whole summary task been shifted left or right. The other two summary tasks (line 12 and 22) also shift though and I do not understand why... I did not declare any dependency between them.

In any case, I guess that with this approach this means that I will have to manually change the phase 2 start date of the hundreds tasks I have. Correct? This is gonna be difficult for me..

What I am trying to do is to "link" the phase 2 tasks of ALL my summary tasks with a milestone called 'PICK UP DATE' so I would only have to move the milestone and the respective linked tasks would be adjusted automatically. I would like all phase 2 tasks (i.e. lines 7, 17, 27) to start at the same time. This means that depending the duration of phase 1, some summary tasks should start sooner than others.

I am still struggling with the dependency of this one, let me know if you can help! How could I link a milestone to my phase 2 tasks without messing with the sequential sequence of my tasks? Adding multiple dependencies in phase 2 task, makes things worse I think..

Regards
Nantia

Attached Files

nantia_problem1.zip (492.3 KB, 9 views)

Happy new year to you too
I will have a look at his tomorrow- its too late to think properly at the moment- but it sounds like it should be fairly solvable. Have a look tomorrow after work, and see if I can find a simple (ish) solution.

Sorry for being a bit late, work piled up a bit last week.

I have had a look, and think we might have something that will work.
First thing is to remove the summary task links. This maintains task relationships, and summary's can get confusing. a link between tasks is a "real" link- x follows y- a link between summary's is slightly different.

Looking at the constraints- you have the pick up date as "no earlier than" which is fine. I have linked this as predecessor of all phase 2 tasks, which keeps them in line. Phase 3 follows from 2, so they will automatically line up.

Phase 1 did make me think. Setting "as late as possible" was pushing phase 2 out, as this forces everything after it out as far as possible so destroys the phase 2 link. If we link the phase 1 activities to the Pick up date, and then set "as late as possible", it works again as the pick up date is the restraint. I have included this as the first solution.

SUMMARY
Removed the summary links, replace with task links
Phase 1 tasks linked so that Pick Up date is a successor to them, then set phase 1 tasks "as late as possible" (note that you only actually need to change the first task, anything following will be pushed back)

Thats about it.

The one thing that does occur is that the phase 3 dates change, I dont know if this is what you wanted but it does link them correctly. See how it goes, can always change it around again.

Oh- the board now allows mpp files to be uploaded, so no need to zip any more.

Attached Files

nantia_problem2.mpp (292.0 KB, 9 views)

I cannot thank you enough Guloluseus!
I understand your comments, I am playing with this and looks good!
many many thanks for your amazing help!

Glad it worked out in the end. I wasnt sure if this would give the desired result, so its nice to know I hit the mark.