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But-for schedule?

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Forum Guest
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Hi planners!

Id appreciate getting your advice on this.

I am facing a situation where I need to show the net negative delay impact resulting from the owners extended durations in reviewing/approving submittals. My idea was to develop a but-for schedule showing the new finish date based on normal planned durations. The problem is : successors activities actually never start the following day after AF according to their FS relation. They sometime begin long after the rev/app activity is completed and sometimes it even starts long before it began! So, if I change the extended durations from actual to planned, what will I be doing to the successor activities to show the impact. Note that these are actual dates, so another obstacle Id face is how the transfer any impact on the entire successor path.

One idea I thought of is to utilize another method where I would start with the latest activity and go through the driving predecessors only until I reach an extended rev/app activity change it and with the same amount globally change the successors. Then continue with the predecessors until the project start using the same method. Using this method, I wont need to go through maybe a 1500 activity, instead only driving activities need attention.

Any other ideas or any comments!?

Replies

Joel Gilbert
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If I understand your problem correctly, why dont you filter all your activities that you require a answer for,copy it into excell and subtract your actual finish from your Target finish, that would give you your delays and then you can even give reasons why delayed etc.

Hope I understood your problem correctly.
Clive Holloway
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A word of advice - simplify / summarise the schedule to a more manageable size, before you start the but-for process.
Abd SiWa
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Mohamed,

Unless I am missing something here, what you are looking for should be pretty simple.

Its a commomn practice to keep various versions of the schedule, including the very first one (popularly known as Baseline), before any progress data was added.

Select the version you want to compare with your current schedule. Copy this schedule in the folder where your current schedule is residing.

(Following is the tricky bit). Make the old version as your current schedule and assign the actual current as Target 1 to this schedule.

You can now filter all the critical activities and compare them by adding another bar for the assigned Target. You could also have various current and target values in the columns for easy comparision.

This should work unless you have addedd significant number of activities since the version you are using to compare.

Hope that helps,

AWADOOD SIDDIQUI
Mohamed Gebriel
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Ronald,

Thanx very much for the advice.

The first option is almost impossible to work on my case as were talking about a 6000+ activity schedule with several paths due to the existance of 12 seperate milestones each needing an individual analysis.

Interpolating points to create critical paths will actually consume a lot of time and Im really not sure of how the results would come out.

On the other hand, I took a look at the site. I liked the product ideas very much. I believe they would make a hell of a difference with delay analysis jobs. You certainly will hear from me soon.

Thanx again.
Ronald Winter
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Mohamed,

The way most analysts determine if completed activities were on the critical path is to take two known points and interpolate between them. In this case, look at the most recent schedule submitted just before the activities in question were statused. What was on the critical path? Then take a look at the next schedule and ask yourself the same question. Now, connect the two events in your mind.

The actual critical path should have started with the active, critical activity or activities in the early schedule and end at the critical activity or activities in the later schedule. The activities in the logical chain between these two activities should reasonably be inferred to have been critical as well.

Of course, this reasoning doesn’t always work. The two active and critical activities might not even be in the same logical chain. The later schedule might have new logic or an unexpected added event that changed everything. That is where you need to go day-by-day using the logs and logic in determining the actual critical path.

There is another way, but I hesitate to mention it. It works extremely well and is easy to use. It is fairly new but professional delay analysts are beginning to use it even in court situations. The problem with me mentioning it is that I am the developer and I hate people pushing advertisements into this forum. It is called Schedule Analyzer Schedule Destatuser. Destatuser takes a completed P3 schedule and ‘walks’ it backward day-by-day to uncover the actual critical path. You can read more about this on www.RonWinterConsulting.com. Good luck!
Mohamed Gebriel
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Hi Tara,

First of all, thanx for your suggestion. I can say your approach is really nice and it deals with this issue in a different but simple method of analysis. I will still have the problem of obtaining the critical path of completed activities. P3 woould not filter neither driving paths nor critical activities for completed activities!? Or am I wrong??

Of course filtering driving relations in the trace logic window wont help cuzz I need the activities filtered in the activity table to be able to work on them.

Waiting for your answers!
Tara Muddappa
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Hi,

The subject chosen is very interesting and tricky as well. As I understand the question is how do we separate the “Net delay” caused by the employer particularly reviewing a submittal for approval?

In my opinion to start with I am in agreement with Mr. Ronald’s comment. We need to identify the path, which are critical or approaching critical i.e. Negative float.

In our project the contract specifies 21 calendar days for review for approval and 14 calendar days for resubmitting back to the engineer.

So I suggest for a given set of activities which needs window analysis, we need to make a tabulated format with headings baseline activity, AS, AF, Actual Dur (Y), Duration allowed as per baseline (X), Gain or Loss, Employer risk event. The columns Gain or Loss = X-Y and ERE = Cumulative days of delay contributed by the employer.

In conclusion if for example the negative float got is –60days and the employer delay is –40 days then we are entitled to claim only 40 days.

Regards to all,
Mohamed Gebriel
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Hi Ronald,

Actually, this is exactly why Im doing this excercise; to be able to know if their late review/approvals have impacted the completion date or not. I wouldnt be able to know the answer if I dont calculate the impact.

I cant refer to the contract conditions neither if I dont know what Im facing here, so its a matter of data collection anad analysis before I continue taking other actions (probably claims). The point is I need to do this impact analysis in a correct way.

Id appreciate any suggestions on how I would transfer the duration cuts I make to these activities to their successsors.
Ronald Winter
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The first question you have to ask yourself is, “why do you have to show the net negative delay impact resulting from the owners extended durations in reviewing/approving submittals?” Did any of these late reviews actually delay the completion of the project or was the Owner just using up some project float?

Then you need to address what your contract and specifications say about this situation. In most cases, Step 1 is almost always notification of potential claim. Analysis independent of the contract requirements is perhaps wasted time. Good luck!