I think people are confusing Gerrys question as being related to Primavera, Power Project, Microsoft Project or some other software, all of which require the relationships you refer to if a CP is to be established. He did not put his question in the context of software, and neither am I talking about software, forward / backward passes, early / late dates or the like.
The connection between as-built critical path activities does not have to be physical, logical, resource dirven or otherwise - the connection is simply that it was critical at the time (as reasonably and retrospectively determined -assuming of course it is possible to so determine from the available information).
Consider that an event that occurred (e.g. the collpase of a portion of structure) might make the crtical path switch between two completely unrelated unlinked activities.
In regards to the points made by others in regards to the ABCP as determined via software, I dont disagree! Sorry about the double negative.
Regards
David
Member for
21 years
Member for21 years
Submitted by Philip Jonker on Wed, 2005-01-05 07:34
I think the point you make is probably very valid, however, I have been in both camps, and still think that the ABCP is a figment of the imagination. Lets take it that the planner has regularly saved all the history including the float at every update and at the end of the project you tack every activity that was critical at any stage of the the project, and then try and find the connection between them. We have mostly agreed tha the critical path can jump around on most projects, so lets say tha you have now now isolated all those activities that was critical, the chance will be good that you may find they are unconnected. How are you going to explain that to a judge or arbitrator David?
Regards
Philip J
Member for
21 years
Member for21 years
Submitted by Philip Jonker on Wed, 2005-01-05 07:32
I do not agree with the idea previously raised to agree to disagree. For the sake of our profession, I think this important argument should be finalised one way or another.
It was suggested before that the issue be put to a vote. Maybe this is the right time to put the issue to a vote notwithstanding that the debate can continue.
Its also noteworthy to see the trend of those believers in ABCP and non believers as to what background they come from.
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
Im on the planning practitioners side thats why I believe As-built CP is not the right term and can not exist.
I am with those who think ABCP does not exist. My understanding of the CPM is that you do Forward Pass for the Early Start and Finish Dates, and then Backward pass for the Late Start and Finish Dates. Activities are Critical if ES=LS and EF=LF, i.e. when there is no Total Float. The fact that the Critical Path is the longest path in the Programme is the result of the previous process - it is not the definition of the Critical Path.
How can you do that with ACTUAL DATES??? in the AB Programme there are no Early or Late Dates - so how can there be a Critical Path?
Does your planning software (P3, SureTrak or even MSP) show a Critical Path for Actual Dates?
However, I am not sure about one thing:
In Contracts where the Contractor is entitled to EOT only for ACTUAL delays to the Date for PC, how do you know which delays actually effected the actual date for PC i.e. which delays were Critical?
As to your suggestion "agree to disagree", Ive got two points:
First, while some in this forum have said the ABCP doesnt 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 Gerrys 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 doesnt exist as opposed to the point that its difficult / subjective to determine - any takers?
David
Member for
20 years 11 months
Member for20 years11 months
Submitted by Philip Rawlings on Tue, 2005-01-04 08:57
Its not an IT answer. The point Im trying to make is that As-built usually (wrt. drawings etc) means based on fact - so we can have as-built start/ finish dates. You say that determining the ABCP path depends on experience, common sense, etc. I totally agree. My point is now that we have a CP which is subjective - so whatever it may be it cannot be called As-built, its subjectivety should be admitted. Nothing wrong with that but it should not be called As-built.
I believe we have seen two (I think only two) points of view in this thread. Probably all that can be said has been said - we now need to agree to disagree!!
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
Member for
20 years 11 months
Member for20 years11 months
Submitted by Philip Rawlings on Tue, 2005-01-04 08:06
It seems we are going around in circles here. Because a judge (or similar) thinks that he/she understands the concept of an As-built Critical Path does not mean it exists, or if it does that the definition is universally held.
The crux as pointed out recently is to show the longest path through a project after the fact. Actual start/finish dates can be said to be fact (if records are full and correct) but there is nothing factual about the links. If you can demonstrate the Actual logic then you can have an actual critical path, otherwise the CP is a mixture of fact and conjecture. One should be very wary of telling a tribunal (or similar) that a critical path that mixes post-project fact with original or amended logic is the As-built CP. We have presented pseudo-as-builts BUT with the clear proviso that the plan logic is reconstructed with best endeavours - not fact!
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.
I echo Davids remarks. In the context of this forum the As-Built Critical Path term is very important and fundamental to any time-related claims.
Gerry McCaffreys original question was, "I am trying to elicit views from real planners discussing the concept of an as-built critical path. Does such a thing exist?"
In my view it does; but it can not be simply generated from the original as-planned baseline network using the planning software in which it was created. IMO it is created from a thorough manual investigation of progress records and other documents. In reality this is the chain of activities that is the longest continuous path of activities between project start and project completion. However, in the claims context this is commonly known as the As Built Critical Path.
Member for
22 years 10 monthsRE: As Built Critical Path
Hi Philip,
I think people are confusing Gerrys question as being related to Primavera, Power Project, Microsoft Project or some other software, all of which require the relationships you refer to if a CP is to be established. He did not put his question in the context of software, and neither am I talking about software, forward / backward passes, early / late dates or the like.
The connection between as-built critical path activities does not have to be physical, logical, resource dirven or otherwise - the connection is simply that it was critical at the time (as reasonably and retrospectively determined -assuming of course it is possible to so determine from the available information).
Consider that an event that occurred (e.g. the collpase of a portion of structure) might make the crtical path switch between two completely unrelated unlinked activities.
In regards to the points made by others in regards to the ABCP as determined via software, I dont disagree! Sorry about the double negative.
Regards
David
Member for
21 yearsRE: As Built Critical Path
Hi Sigfredo,
I think the point you make is probably very valid, however, I have been in both camps, and still think that the ABCP is a figment of the imagination. Lets take it that the planner has regularly saved all the history including the float at every update and at the end of the project you tack every activity that was critical at any stage of the the project, and then try and find the connection between them. We have mostly agreed tha the critical path can jump around on most projects, so lets say tha you have now now isolated all those activities that was critical, the chance will be good that you may find they are unconnected. How are you going to explain that to a judge or arbitrator David?
Regards
Philip J
Member for
21 yearsRE: As Built Critical Path
[Duplicate posting deleted by Moderator.]
Member for
21 yearsRE: As Built Critical Path
[Duplicate posting deleted by Moderator.]
Member for
22 years 5 monthsRE: As Built Critical Path
Sigfredo,
Interesting observation.
How about a survey to check your point?
I do not agree with the idea previously raised to agree to disagree. For the sake of our profession, I think this important argument should be finalised one way or another.
Member for
24 years 5 monthsRE: As Built Critical Path
Hi guys again,
It was suggested before that the issue be put to a vote. Maybe this is the right time to put the issue to a vote notwithstanding that the debate can continue.
Its also noteworthy to see the trend of those believers in ABCP and non believers as to what background they come from.
Se
Member for
24 years 5 monthsRE: As Built Critical Path
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
Im on the planning practitioners side thats why I believe As-built CP is not the right term and can not exist.
Se
Member for
22 years 5 monthsRE: As Built Critical Path
Guys,
I am with those who think ABCP does not exist. My understanding of the CPM is that you do Forward Pass for the Early Start and Finish Dates, and then Backward pass for the Late Start and Finish Dates. Activities are Critical if ES=LS and EF=LF, i.e. when there is no Total Float. The fact that the Critical Path is the longest path in the Programme is the result of the previous process - it is not the definition of the Critical Path.
How can you do that with ACTUAL DATES??? in the AB Programme there are no Early or Late Dates - so how can there be a Critical Path?
Does your planning software (P3, SureTrak or even MSP) show a Critical Path for Actual Dates?
However, I am not sure about one thing:
In Contracts where the Contractor is entitled to EOT only for ACTUAL delays to the Date for PC, how do you know which delays actually effected the actual date for PC i.e. which delays were Critical?
Member for
22 years 10 monthsRE: As Built Critical Path
Philip
As to your suggestion "agree to disagree", Ive got two points:
First, while some in this forum have said the ABCP doesnt 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 Gerrys 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 doesnt exist as opposed to the point that its difficult / subjective to determine - any takers?
David
Member for
20 years 11 monthsRE: As Built Critical Path
David
Its not an IT answer. The point Im trying to make is that As-built usually (wrt. drawings etc) means based on fact - so we can have as-built start/ finish dates. You say that determining the ABCP path depends on experience, common sense, etc. I totally agree. My point is now that we have a CP which is subjective - so whatever it may be it cannot be called As-built, its subjectivety should be admitted. Nothing wrong with that but it should not be called As-built.
I believe we have seen two (I think only two) points of view in this thread. Probably all that can be said has been said - we now need to agree to disagree!!
Member for
22 years 10 monthsRE: As Built Critical Path
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
Member for
20 years 11 monthsRE: As Built Critical Path
It seems we are going around in circles here. Because a judge (or similar) thinks that he/she understands the concept of an As-built Critical Path does not mean it exists, or if it does that the definition is universally held.
The crux as pointed out recently is to show the longest path through a project after the fact. Actual start/finish dates can be said to be fact (if records are full and correct) but there is nothing factual about the links. If you can demonstrate the Actual logic then you can have an actual critical path, otherwise the CP is a mixture of fact and conjecture. One should be very wary of telling a tribunal (or similar) that a critical path that mixes post-project fact with original or amended logic is the As-built CP. We have presented pseudo-as-builts BUT with the clear proviso that the plan logic is reconstructed with best endeavours - not fact!
Member for
21 years 11 monthsRE: As Built Critical Path
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
Member for
24 years 5 monthsRE: As Built Critical Path
I echo Davids remarks. In the context of this forum the As-Built Critical Path term is very important and fundamental to any time-related claims.
Gerry McCaffreys original question was, "I am trying to elicit views from real planners discussing the concept of an as-built critical path. Does such a thing exist?"
In my view it does; but it can not be simply generated from the original as-planned baseline network using the planning software in which it was created. IMO it is created from a thorough manual investigation of progress records and other documents. In reality this is the chain of activities that is the longest continuous path of activities between project start and project completion. However, in the claims context this is commonly known as the As Built Critical Path.
Roger Gibson