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Find the driving predecessor

26 replies [Last post]
Jason LI
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Dear all,
If one activity have many predecessors, how to find which one is a driving predecessor.

Many thanks!

Replies

Rafael Davila
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WHAT IS DRIVING MY SCHEDULE? I WANT THEM ALL: LOGIC LINKS, RESOURCES OR CONSTRAINTS.

With MS Project I can see Logic Drivers, Resource Leveling Delays and Driving Constraints all in a single pane, not bad.
MS Project Task Drivers
MS Project Task Drivers 3
All software should have similar functionality plus a tabular report listing similar information for all activities, or a protion when filtered.
Mike Testro
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Hi Jack

Did you find the driving predecessor?

If so how?

Best regards

Mike Testro
Jason LI
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Thanks all your guys
Alexandre Faulx-B...
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Rafael,
you are 100% right, and I 100% agree to your post: MS Project was something simple and good, and unfortunately MS marketing people have decided it should be something much more sophisticated; but people at conception and development did not succeed in producing something good.
I am starting writing several articles and books about MS Project 2010 for the French market, and almost everyday I find something that does not work properly.
MS Project, any release you would use from ’98 to 2010, is a drawing tool with a simple computing machine, it is not such a scheduling engine as P3, Powerproject, Spider or Sciforma’s PSNext
All the best,
Alexandre
Rafael Davila
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Alexandre,

I have come to appreciate the value of MS Project up to the point I believe if more and more is added to it then its purpose of being a useful tool for those in need of a simple tool will be lost forever. Most managers can manage their jobs with simple bar charting, with some extended functionality even better, here MS Project shines as no other, for many the intricacies of many CPM functionalities are more of an obstruction.

I would like MS Project to display true vales for float after resource leveling, this is not a request for additional functionality but for a correction. Displayng wrong float on a resource leveled schedule is misleading. If this is done then I would not feel the urge to raise the flag.

On my part two thumbs up with MS Project, noting wrong if some functionalities are omitted in MS Project, on the contrary.

Best regards,
Rafael
Alexandre Faulx-B...
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Rafael,
obviously Jack would like to find in MS Project the same kind of info you are displaying in Primavera Suretrak or P3; the problem is Jack is working with MSP and not with a Primavera piece of software
therefore your last post is useless for Jack, or it only results in additional frustration
the fact is: MSP 2003 and earlier cannot show the driving predecessor in any way; MSP 2007 and 2010 have a feature called Task Pilot in 2007 and Task Inspector in 2010, that shows why a specific task is being scheduled at such a date: either because a driving link, or a scheduling constraint; they also show which resource is working on the task and if a specific calendar was assigned to the task.
Jack should upgrade to MSP 2007 or 2010.
Alexandre
Rafael Davila
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Trace Logic

I believe Jack is looking for someting like the above predecessors table that identifies the driving predecessors. This is a complement of the Trace Logic View I would be using 5% of the time while 95% of the time I would be using the table, this is the answer he is looking for, but with regard to MS Project.
Rafael Davila
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Mike,

Your schedules are of less than 30 activities due to oversimplification and use of laddering but maybe Jack LI have hundreds of activities whose links are spanning several pages, here displaying the links at the Gantt view is of not much help, in any case a distraction.

In the case of a very large network even the traditional PERT diagram might be kind of limited, unless it provides the functionality to trace logic the way P3 and SureTrak do, displaying with different line types the links and filtering out boxes not linked to the selected box here you will find far boxes right next to the selected with control as to how many levels you want to display. In MS Project I believe you can only differentiate here between critical and non critical links, to differentiate for links that are moving your activities is not available. Many consider this diagram essential to the understanding of your logic and I agree, but only if it includes the functionality to trace logic. I don’t know if MS Project provides you with a trace logic functionality that will tell you if the link is moving your activity. I have seen software that claim to be serious CPM software but do not provide even the basic PERT diagram.

How good is Asta Power Projet at displaying PERT views?

Jack need an answer about a functionality found in almost all software, his question has been partially answered with regard to resources and maybe with regard to date constraints that also can be the drivers of the activities, in either case a vertical line at the Gantt View in a 2 activities schedule can miss the correct answer when an activity is moved by a resource or a date constraint.

Jack is still missing the other part, is still an incomplete answer. To me, even Trace Logic PERT diagram is still not enough, is a complement to the tables Jack is looking. Software that misses either is bad software.

In addition to what Jack is looking I would like to see at the resources table a column that displays on each resource line which activities are moved by the particular resource after the resource leveling. I would like to see a constraints table displaying on each constraint line which activities are moved by the constraint and if the constraint was met or projected as not to be met. In my opinion all software, without exception, are missing good functionality to figure out the logic of your schedule even when the knowledge to provide the functionality is there. A request our friend Ron Winter have been asking for years, to make the schedule “Transparent”.

Best regards,
Rafael
Mike Testro
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Hi Jack

Go back and read thread Nr 6.

Best regards

Mike Testro
Rafael Davila
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Jack LI

I cannot tell you if MS Project display information about driving predecessor when logic takes control over resource constraints but if not it would be of great disappointment to me. YOU AR RIGHT IN YOUR REQUEST AS THIS HAS NOT BEEN PROPERLY ANSWERED YET.

All software I have ever used does show the information you are asking, therefore my conversation moved to the theme of identifying when your activities are driven not by logic but by resource leveling. I assumed someone else at this time would have given you a direct answer as to when precedence logic is in control.

In the case of MS Project when resource leveling takes control the answer to your question is in the Leveling Gantt View. In MS Project the Leveling Gantt view will display task leveling delay.

All software can generate the Leveling Gantt but not necessarily using a pr-defined view. Simply create a baseline with your schedule unleveled and compare with the schedule after leveling. You can use formulas and even graphic indicators to highlight those moved after resource leveling. If your activity has a single resource assignment you by default know the driving resource if multiple resource assignment then you still do not know which is delaying/driving.

Don’t ask me about the resource that created the task leveling delay when the activity has multiple resource assignment, ask the resource leveling algorithm. How? Have no idea.

Very few software can tell you true float.

Hope the following illustration is of help to some of you. As you will notice all activities are initially scheduled in parallel with no logic relationship to any other. After resource leveling Spider Project display no available float, does your software agree?

Resource Driven

Please those proficient with MS Project answer the question of Mr. LI with regard to precedence logic.

Best Regards,
Rafael
Jason LI
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Posts: 37
Thank you, guys, but my question is how to find the driving predecessor in many or predecessor, is it possible or not with MSP 2007. and how can.

manys thanks
Thank you, Alexandre.
Unfortunately I don’t read French.
And unfortunately I don’t read Portuguese and thus can’t read a book on Spider Project published in Brazil.
My daughter can read and speak French, she will have more opportunities.
Best Regards,
Vladimir
Alexandre Faulx-B...
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Vladimir,
I did not say that MSP 2010 is doing well!
I will write something (a 20 page story) about what is new in MSP 2010 for the Association Française de NORmalisation, and then a training book for the main technical publisher here in France.
I will be happy to send you my story if you can read French
Alexandre
Alexandre Faulx-B...
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Samer,
in case the task has a constraint, MSP says it; MSP also shows which resources are assigned to the task; it does not say if a resource is on holiday when the task should start, and therefore is delaying the task
e.g. the last predecessor makes the task to start on jan 21; the SNET constraint makes the task to start on jan 25; the resource does not work before jan 26: the Task Inspector shows that the SNET constraint makes the task to start on jan 25; it says that the atsk will start on jan 26; it says that a specific resource is assigned to the task; it does not say that the resource is pushing the task to start on jan 26.
Alexandre
Alexandre,
MS Project 2010 still shows wrong floats after resource levelling and resource-constrained schedules were not improved.

Hi Samer,
what problem do you see in managing project portfolio with 100000 activities?

Best Regards,
Vladimir
Samer Zawaydeh
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Dear Alexandre,

Thank you for the update. What will happen if the driving predecessor is a constraint or a resouce and not an activity. Can it also show this? Thank you for your response in advance.

With kind regards,

Samer
Samer Zawaydeh
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Dear Rafael,

I am confident that these softwares already exist. Did you know that 50 years ago when they developed PERT at NASA, they were working with 3000 Contractors at the space program! What will happen if you have 10 Contractors on your job with 10,000 activities each. It is a big dish to finish.

With kind regards,

Samer
Alexandre Faulx-B...
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Samer,
in MS Project 2010, the Task Inspector has improved since MS Project 2007:
explanations about why the task is being scheduled as a said date are more complete; there is a link to the driving predecessor on which you can click to jump to this task.
Alexandre
Rafael Davila
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Samer,

My friend, I believe these enhancements are long overdue and that PP community should take a proactive stance and start raising the voice. My postings represent a single voice but maybe it will make others to stop being satisfied and start claiming for these enhancements, and who knows, maybe someone that can make the difference is listening.

Best regards,
Rafael

P.S. I know of one that is listening, so there is a possibility others are listening too.
Samer Zawaydeh
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Hi Rafael,

It is possible that with future enhancement of software, that they will have an analysis feature as well. Expert Systems are all about sitting down with experts, taking their knowlegde and programming it for future use.

With kind regards,

Samer
Rafael Davila
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Samer,

“Of course you have to understand the logic in order to determine the driving predecessor” is a misleading notion under resource leveling.

Logic relationships are not always your drivers. Software that gives you the wrong float under resource leveling is wrong.

If you know true float and that resources moved your schedule this will give you a hint on where to look. Then instead at looking at logic I would start by looking at resources and the activities that use them. Of course I would like my software to tell me which specific resources are driving and which activities by mean of resource allocation, this will narrow my search.

It is bad being fooled by software that display wrong float when in reality it is less than the shown amount or even 0. I believe in advancing the knowledge of scheduling and not being stuck in the 70’s when the more advanced features of PDM were added without expanding the functionalities to understand PDM logic.

Best regards,
Rafael
Mike Testro
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Hi Jack

Normally I look at the screen and see which of the links is vertical - this will be the driver.

In Powerproject you can set the vertical links to be curved so that you can trace them clearly.

Best regards

Mike Testro.
Samer Zawaydeh
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Dear Rafael,

If you press resource leveling, then chances are that you will not know what happened!

Of course your have to understand the logic in order to determine the driving predecessor. Usually, the Program of Works is studied and analyzed by the project team, and the delays and the construction sequence is fine tuned or depated repeatedly until it is proven that it is the best course of action.

With kind regards,

Samer
Rafael Davila
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What if an activity is moved by resource leveling? Who will be your activity driver? What if moved by a Constraint other than resources; can it be a date constraint, can it be other such as financial constraint?

It might be that none of your logic predecessors is driving your activity.

What is driving my activities is one of the questions I always ask.
Ferdinand U.
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Samer Zawaydeh
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Dear Jack,

I did a small search over the net to find the exact definition and if you do the seach for the following you will find the answer is the Driving Predecessor is the predecesor that determines the Early Start of a task.

Search for:
Planning and scheduling using Microsoft® Project 2007 including Microsoft ...

With kind regards,

Samer