Hi guys,

Am i right on my observation that most who believe that As-built critical path comes from Contracts/Claims background while those on the opposite side are mostly Planning practitioners. Just asking

I’m on the planning practitioners side that’s why I believe As-built CP is not the right term and can not exist.

Se

Philip

As to your suggestion "agree to disagree", I’ve got two points:

First, while some in this forum have said the ABCP doesn’t exist, none have offered a clear reason why they reach this view. Your comments do however capture the matter which I think the following suggestion resolves?
Can we agree the ABCP exists (thereby answering Gerry’s original question which has stirred so much debate), while recognising that any view as to its route is subjective, i.e. an opinion?
Of course, an opinion is precisely how it would be appropriately characterised to a court / tribunal in any event (as Garry has recently done).

Second, it would be a shame to cut-off debate, so lets continue to canvass views. In particular I would really be interested in hearing clear justification for the view that it doesn’t exist as opposed to the point that its difficult / subjective to determine - any takers?

David

Philip

I think you are giving an IT answer to a planning question. Locating the as-built critical path is best achieved by the application of experience, skill, and common sense. The occasional and careful use of programming data and software (links et al) is a useful tool but only that!

The As-Built Critical Path must exist - its a matter of physics IMO. Had Gerry asked "is it always possible to locate the ABCP?" then subjectivity might reign!

David

Having watched this thread with interest, it is clear that there are two distinct camps of thought here – there are those who believe an as-built critical path cannot exist and those who do use them. I have to say I am in agreement with Roger and David that an as-built critical path must exist, for people, me included, draw them as part of delay analysis and delay claims.

Having recently presented an as-built critical path to a judge in a delay analysis claim, that judge certainly believes in such a document and terminology. David is right when he says clients, courts and tribunals are constantly looking for assistance from experienced project planners on this subject. In my experience, courts do want to know what was the critical path through the project even though that project may have been completed a significant time ago. An as-built critical path is exactly what they are looking for.

Best wishes

Gary France
Chairman
Planning Engineers Organisation

Philip

Your sentiments are well voiced and received - but remember, you’re writing them in a forum entitled "Contracts, Claims & Claims Assessment". While no one can criticise your idealism I think you ignore reality - i.e. that it is (alas) often very very relevant to determine historically what was critical on a project at a prior point in time.

Clients, Courts and Tribunals are constantly looking for assistance from experienced project planners on this subject - surely you can’t be suggesting they are seeking answers to an impossible question?

A Happy New Year to you and all the other forum participants also.

David

Gerry et al

Being an "As-built critical path ’o-phile" I’ve found the thread interesting.

It seems to me that the answer has to be yes - it exists!
Subject to the information being available a skilled planning analyst can surely advise what was critical at any point in time on the project. If we also believe the critical path can switch, then surely connecting all the retrospectively determined critical activities together results in (yes wait for it ...) the "as-built critical path".

Of course you could all just be talking about the ability to locate the as-built critical path via programming software (i.e. via a logic linked dynamic as-built programme) then I would say it is possible in threory - its just not reliable!

Gerry - get back to work!

Regards
David

If we can say in retrospect what was critical at any point in time (using analysis) then

Dear Stuart,
please advise me where in the definition of the Critical Path I may find that "a "Critical path" can only apply to the future".
Thank you in advance,
Vladimir

Gerry, I have already been given my opinion at the start of thread and no change in the statement so far.

The simple issue has been so pronloged and discussed to understand the word " As built". I think enough and valuable discussion should come into conclusion now.

Hi Ronald

Maybe the word Right was not correct BUT the computer program (Example P3) is told to calculate the the Longest Path on Remaining Duration. If you program P3 to Calculate on the Actual Duration it will also give you the "As Build CP"

Have you ever had a case were the schedule tells u this is your CP and you know it is wrong then when you check the logic you find the mistake. We must not rely on Computers and belive everything they "Say" is correct.

As far as Politicians go " I have heard politicians say "I have never had ... with this woman" But then again it depends what you define "...." as. So my conclusion are they always tells the "truth" from their perspective.

Cheers

Gerry

Here is a Thought

The Critical Path can only exist in an As Build State.

The Reason
As so many NON Believers have agreed is that the critical path keeps on changing. So if you say something is Critical now it does not mean it is stil critical in a second/Minute/Hour/Day/Week/month from now.

So to see the true Critical Path you can only see it when you have completed the project. (Not before because it is your "current" projected critical path) (Remember a critical path the longest path)

Cheers

Uri,
critical path is by definition the longest path in the network. If I will want to learn what path in my network is or was critical (i.e. longest) I need to look not only in the future but also in the past.
If at the start of the project all activities in my schedule are ALAP then all of them are critical (have zero floats) but still there is a critical path, isn’t it?
Vladimir

I really am at pains to understand why this has been such long ongoing thread. By definition the terms "As built" and "Critical Path" cannot be used together. An "As built" scheduled is one that has been updated with actual starts and finishes, a "Critical path" can only apply to the future. An "As built" can only influence the "Critical path" if the actual dates were later than predicted it would then impact the future dependant activities that have not started, possibly creating a "Critical Path".

Vladimir,

Explain that one please, about the future?

As I have said before, how can something in the past be critical. Therefore only things in the future have the risk of becoming critical.

Regards

Philip

Hi Gerry and all other contributors,

It’s been an interesting one. Thanks all.

An interesting question to PPAdmin what has been the longest thread to date on the site?

Regards

Philip J

Sigfredo,

I agree with you that there is a problem, however to me the problem is not with the term As-built Programme. This term is commonly used and self explainatory.

The problem lies in the combination of As Built with Critical Path, as usually Critical Path relates to the FUTURE and As Built relates to the PAST.

My personnal opinion is that there is no such beast as ’As Built Critical Path’

Gerry
Sorry - I should have made it clear I knew who you were talking to. I just meant to put in my 3-ha’pence-worth!

We are only too weel aware here abpit the EOT issues. Unfortuanately, many of those invloved 9especially rhe lawyers) do not really appreciate thes issues. I think we ought to make a distinction between an as-built schedule (actual dates) that happens to built on a CPM program and a CP schedule (one where the logic is key).

Maybe the only useful question is:

Is there any purpose in looking for an as-built critical path?

Gerry,
we usually create very detailed schedules for construction works with the activity durations that not exceed one week. Contracts define target dates for major milestones and these target dates incorporate agreed contingency reserves.
Vladimir

Happy to know that the wave is seem to be settled on the As Built Critical Path issue ................... Its time for voting as per Philip Jonker’s suggestion.

Philip,
let me express my oppinion:

a) The critical path is an assessment of those activities (from now until the end) that could delay the project if themselves delayed. CP in the past is therefore an irrelevance.

It is not quite true, CP does not take into consideration resource limitations. It is true if resource constraints do not exist. CP in the past is useful for the project performance analysis post mortem.

b) By my definition, therefore, there can be no critical path on completion, so no As-built critical path

As Built Critical Path shows which activities and delays defined actual project duration.

c) An hypothetical CP could be constructed from the as-built schedule (which records actual dates, suspend, resume, resources etc). This is useful in informing the next project, in improving the start-up planning

Right, it is useful for lessons learned and for claims assessment.

d) The reconstructed CP is HIGHLY subjective. If the as-built is to be used for a claim, then avoid any links and restrict the plan content to fact, that which can be evidenced.

Right! That is why I wrote that all delays and their reasons should be documented and included in the project model.

e) Above all, remember that the CP is not factual. It relies on a subjective assessment of the relationship between semi-factual activities. Even when activities have been completed, it is still very difficult to ascertain the ’true’ relationship between them.

I don’t agree with the subjective nature of activity relationships.

d) As to whether there is a CP in a project without a schedule - this is largely irrelevant. The CP is one’s idea of the longest path. If one has no ideas (i.e. no schedule) then one can have no concept of a CP. Again, the CP is not an absolute, it is based only on the assumptions made by those involved.

CP is usually based on the technological restrictions (roof after walls, etc.), it is not based on assumptions.

Hope this adds rather that subtracts!

Yes, you are right. Logical restrictions that were established at the project start should be kept. If they were wrong then it is a cause for lessons learned exersize. But you shall add delays and additional work to the original network.

Sure,
Critical Path may change during project execution and many times. That is why you shall include in As Built Schedule all delays that occured with the description of events that cause these delays. As the result you will see what chain of activities and delays constitutes As Built Critical Path. It does not mean that at any time in the project life this path was critical in the project schedule.

I mean logically linked as-built activities loaded with resources, costs and other actual information that should be compared with the original estimates.
I repeat that during project execution all schedule delays should be included in the schedule preferably like additional activities (delays) or lags, imposed dates are worse for the future As Built Critical Path analyis.

You had logic in the initial schedule. What happens with this logic? You had done the work out of sequence? It means that the logic was wrong in your initial schedule or you decided to use fast tracking. The latter decision should be accepted at some moment and the links in the schedule updated.
I still don’t understand what can happen with the project logic to the end of the project.

As Built Critical Path may be useful for project close out, lessons learned, etc.
I don’t understand many arguments in this discussion. Why everybody agrees that there is not such thing as As Built Schedule? Maybe you mix methodology and tools? Just imagine that you do everything manually. In this case you may update your initial schedule with the actual durations and costs and as the result you will receive as built schedule. This schedule has the same properties as any other, including critical path (only if you add into schedule events causing delays).

[Duplicate entry deleted.]

I agree.
Critical path, besides it is defined as the longest path, is usually defined by TF=0. If no schedule, all the above is not exist and so, what is the measurment criteria?

Hi Gerry

I still say a As Build critcal path exist.
Does a project without a schedule have a critical path.

If your answer is yes then you must define the definition as the longest path & forget about float. (remember the project does not have a schedule). (Differance between planning and scheduling)

Also have any of you used why before. Once you have completed a schedule ask yourself why was the project not finished earlier and then go through the activity’s one by one and ask why was this not finished earlier. Eventualy you will see the true as Build Critical path.



Cheers

Hi Staurt,

I don’t think there is a name for it so just call it the longest path:-) The point being that if the project finished early the longest path was never critical. Further if the project finished exactly on time or late, and the last activity was say "Handover", There would probably have been some other chain of activities linked to the final activity, so it might not necessary have been the longest path activities that forced thee project to end late. So again give one good reason for bothering with a so-called "As-built CP".

Regards,

Philip

Hi Philip,

Yes, I agree – which is why we should stay away from the term “Critical Path” insofar as an As-Built Schedule is concerned. What therefore, would you call the longest line of activities through an As-Built Schedule?
Isn’t this where it all began?

Cheers,
Stuart

www.rosmartin.com

Very interesting thread (now that I have caught up with it!), and I think that we are mainly reading from the same page. I would agree with Roger and Gary about the “snapshot” or “windows” approach – personally, I stay away from the word “windows” to avoid confusion with u-no-what; I prefer to call it “sausage or salami slicing!”

Unsurprisingly, we all seem to agree that the CP runs forward to the end of the project (starting now or at some other point in the future) and we all seem to agree that the CP can multiply and can flit around from day to day. Ronald’s last post (!) emphasises this point. However, I am unsure as to whether this answers Gerry’s earlier question as to what you call the CP once it is consigned to history (i.e., what do you call today’s CP tomorrow when it becomes yesterday??) [Thank God no lawyers are taking part in this discussion!!]

In addition, from a claims entitlement point of view, I would just add that if your Baseline Schedule is itself incorrect and unreasonable (subjective definition anyone??) then the formation of an As-Built Schedule that emanates from said Baseline Schedule, will itself be incorrect.

Cheers,

Stuart

www.rosmartin.com

Hi Sigfredo,

What you say is true. There is one thing however, that is a useful tool, that is saving the history after each each update. P3 has this feature in store period performance. Using this feature has two advantages, one , in that S-curves and histogrammes give a better reflection of actual events, and secondly, where delays occured they can be tracked correctly in the the event of a claim. The value of stored period performance is obviously dependent on the frequency of updates, the more frequnt the updates, the more accurate the stored information. One of the biggest and serious causes of productivity losses is disruption of activities.

Regards
Philip

Hi guys,

Just want to share my ideas on the subject.

1. It is a fact that a Critical Path(CP) today may not be the same tomorrow, next week, next month etc. Unless someone will dispute this fact, please feel free to discuss it.

2. In comparison, as built CP is not the same as as-built drawings. As built drawings can not change meaning if a foundation size on the original plan is 2mx2m and it is actually built at 2.5mx2.5m, no one can dispute that what was constructed is a 2.5mx2.5m foundation because you can easily prove it. In As-built CP it is ever changing. What you may have as an as-built last week may not be the same tomorrow.

IMHO, I believe the word As-built CP is not the most appropriate term. I think History of Critical Path is the better term.

Hi Phillip

Can you please supply us with your definition of the Critical Path.

Thanx