As Built Critical Path

PS Phillip, apologise for some of the grammar in that last post, but then I have just got back from the pub!

Philip,



Quite easy to build, not so easy to get right! If you update a programme (not the master, but a copy as you end up changing most of the links, adding lots and lots of activities, etc - do I hear a cry of horror from some people) as the project is built to reflect what has been done, why and what is remaining to do you will have a critical path at each update - part as built, part work to be done. So whats the difference I hear you ask from just updating the master programme?



It needs to be in ALOT of detail - I often build mine up from the daily plant and labour allocation sheets. Agreed it won’t show the whole as built picture and critical path until the end but it will demonstrate if done correctly a snapshot of the job at every update showing what, why, and when everything was done (I also like adding lots of notes to the programme)- very useful reference which can if required be compared to the master copy and it’s updates - they usually tell a different story as the master programme rarely contains enough information to get to the finer detail.



People don’t like changing the baseline master programme logic or activities for obvious reasons, some of which have been expressed in here, however I have sat with many a client / claims expert and produced the "alternative as built" programme and used it to demonstrate the course of events, normally backed up by documentation both during and after the project - haven’t had one take me to court yet!!!



People seem to get hung up on the master programme and believe it to be the only programme you can use to prove your case. Not entirely true - although it does normally carry greater weight than others - but if you can demonstrate that the other programme is a true reflection of events, then it’s as good and relavent as any other evidence - coming back to Egger (sorry) but right is right, wrong is wrong and you can dress something up as much as you like but you won’t beat a right call presented properly.



It has given me a considerable pleasure over time to unexpectedly produce to others a very detailed as built programme when discussing events / claims - the conversations tend to be quite short after they see it!



To get to your as built critical path Philip takes alot of work and time if it’s going to truely reflect events and therefore be useful. Strictly speaking, no you don’t have a complete ABCP until the end of the project but believe me, having that a part built one available at any time during a project can prove very useful. Hope this helped.

Hi Andrew,



I am still awaiting an answer to my question?

David,

Your thought appear pretty spot on to me. I don’t think anyone is getting personal, at the end of the day two cases to an arguement were put forward to be judged, one won the day the other did not. It is just unusual in this case that the wording of the judgement was so damning of the evidence put forward by one side, quote:



"there were times when the impression was created that Mr KP was not entirely familiar with the details of the report....",

"..used untested judgement of others in selecting and characterising the data for input into the computer program...."



We can all run around being polite and bury our heads in the sand saying that nothing was amiss and that KP and crew were hard done by or we discuss the facts and learn by it. Discussing the polite niceities and ignoring the facts won’t learn us anything.

Uri and all…



I agree totally that we do need the participation of as many PPers with knowledge, especially the specific and intimate knowledge, of the topics we are discussing. I also found your conflation of ‘respectable persons’ in your opening sentence amusing.



The Skanska case is important for planners and experts. Too few of these cases come to the TCC and are reported so widely. In a fast-moving discipline such as ours it is important that we know what the Courts are thinking, although they may not be precedents, they do give some pointers as to future conduct and what can be expected from expert witnesses and we all have lessons to be learnt.



It is also relatively rare that there is such a large amount of verbatim reporting in a judgement. As voyeurs we can only read the official reporting (lets say the Judgement in this instance) and what other learned commentators say about the matter. KP’s insight into the case is valuable as he has first-hand knowledge and is able, like Gary has done, correct some of our misconceptions or wrong inferences.



However what I object to is that you think some members of the forum are being too personal and not professional, you are of course entitled to your view but we need to share knowledge and respond honestly and openly to questions. In KP’s second posting of 22 March (I am not sure I was hard done by but I am sure Egger were as I am equally sure Laing were…) he makes some very pointed observations regarding the Skanska and GEH cases. I have only read the Judgements and reports on those cases, although I do know Gary, Tony and Jim, so maybe I have to make inferences and sometimes do jump to the wrong conclusions. If we are to believe what Gary says about the GEH then KP, it seems, is also guilty of coming to the wrong conclusions. I think it unfortunate that KP, in his subsequent replies, chose not to clarify my, and others’, misconceptions about what method of analysis he used in the Skanska case.



As for the issue of facts; it might be worth reading the SCL’s draft of the ‘Anti-Corruption Code for Individuals in the Construction and Engineering Industry’ (downloadable at http://www.scl.org.uk/papers/pdfs/121-stansbury.pdf). Section III, paragraphs 36 to 47 are about dispute resolution. There might be a few pointers here. It seems to me that it is acceptable to rely on ‘facts’ told/instructed by their clients so long as it is made clear, in the evidence, that is what is being done. As far as rejecting facts, that seems to me to be an oxymoron, a fact is either a fact or it is not (it could be an opinion, or an assumption or whatever else) and again so long as it ids being made clear that it is an opinion, assumption or whatever in the light of no supportable evidence then that should be okay. If there is no sufficient documentary evidence, statements by ‘witnesses of fact’ may assist here (rules and guidence can be found here: http://www.barcouncil.org.uk/document.asp?languageid=1&documentid=578).



As usual I should add that I am not a lawyer and my opinions may contain inaccuracies, inferences and downright lies!



Regards



David

Uri,



I do not think it is appropriate to rely on the untested information gleaned from your client. Where it differs from that of the opposing side, the Expert Witness should either carry out his own independent determination or present a range of opinion covering both propositions.



Not sure what this all has to do with ABCP!



On that subject Great Eastern certainly makes it clear that the courts consider the ABCP exists - while there continues to be some disagreement in this forum on the subject.



I think Gerry summed it up much earlier in the debate when he said the disagreement seems to stem from the word "path" rather than the ability to analyse/identify what was critical on a project at any given time in the past (assuming as Keith points out the information is available to do so).



David

www.preceptpm.co.uk

Hi Andrew,



Please explain how to build an ABCP any other way than retrospectively?

Guys,

I think we want and need the participation of KP and other respectable persons, so lets continue to be professional and stop being personal.

As for the issue of ’facts’, to what extent do you think the expert witness can rely on what he / she is being told by their clients (and reject the ’facts’ as presented by the opposing side)?

If there is no sufficient documentation, how can the expert witness test these facts?

Happy Easter from down under.

Seems the Egger case keeps coming up in various threads - hot subject of debate.



Firstly to answer the question, yes an ABCP can exist, trying to build it to reflect events with a high degree of accuracy is very very difficult especially retrospectively. It’s hard enough if your’e there at the time and know all the in’s and out’s first hand.



Secondly, KP and Egger, having read the proceedings a few times now along with some other articles I can only conclude that David’s comment on quality and reliabilty of evidence hits the nail on the head. Either KP was chasing a number of less than 100% justifiable claims on behalf of his client (now none of us do that do we) and so had to try and make the evidence fit the claim or the team putting the evidence together were at fault (or both). Also KP’s preparation and understanding of that evidence would appear to be questionable from comments made in the case.



As for the conspiracy theory put forward that authors of the Protocol are being singled out and systematically trashed by the legal system, I don’t really think so!!



Lesson to be learn’t - a claim put forward in a clear and concise manner with sufficient and proven documented evidence will win.



[Note from the Moderators: If what you intend to say is too impolite to type directly, why do you feel that it is acceptable to leave out the vowels but type it anyway? Does this technically absolve you?]

Keith,



You were not quite correct when you said “…in GEH the contractor was found to have caused 100% of the delay neither the works contractors nor the design team having caused any at all. Both results are inherently improbable and contrary to experience.” For example, in paragraph 131 of the judgment, reasons are set out for the delays not caused by the contractor (actually, Laing was a construction manager).



You also said “In neither case was the Judge aware of what was in the experts reports.” In GEH this was definitely not correct. It was very apparent that the Judge took a great deal of time to read both of the Experts’ reports and knew the contents well.



There are similarities between the two cases, but there are also significant differences, the main being one centred around the role of a contractor and the other the role of a construction manager.



Gary France

Mace

Keith and all…



Thanks for your reply.



Who ever suggested it was anything other than a serious discussion? However, I stand corrected but knowing that you are a proponent of TIA and that the judgement refers to it as a ‘sophisticated impact analysis’ and ‘of some hundreds of pages supported by 240 charts’ I think I and others have made the reasonable inference that you were probably using TIA.



As I said previously, we need some definitions of the methods we use so that we can all learn and identify. Garry France was good enough to relate some of his experiences in GEH, in particular to help identify the methods of analysis that both experts used, I do believe, in that Judgement there was some confusion in descriptions.



Maybe you would like to enlighten us as to the method you did adopt? I do not think that is really the important factor here though. Some commentators have sought to suggest as a result of this case that sophisticated computer-based analysis techniques should not be used. That is a great disservice that has been done to our discipline whereas the real problem was the ‘unreliability evidence based upon his inadequate research and checking’ and other such criticisms.



So, do I recognise a pattern in Egger and Great Eastern Hotel cases? Yes, unfortunately, I do.



Regards



David

I don’t take it personally. Heavens, if we did that how could we be impartial.

I am not sure I was hard done by but I am sure Egger were as I am equally sure Laing were.



In terms of similarities how about:



In Egger the the employer was found to have caused 100% of the delay to completion, the contractor and its sub-contractors being found to have caused none; in GEH the contractor was found to have caused 100% of the delay neither the works contractors nor the design team having caused any at all. Both results are inherantly improbable and contrary to experience.



In Egger the Judge found Egger had behaved badly by screwing the contractor down on price and then not giving it an EOTs during the course of the works. In GEH the judge found the CM had behaved badly by falsifying its programme updates.



In Egger I relied in the case of 2 events out of 120 on some evidence provided by my client and my analysis never got past first base. In GEH Tony relied on some of the evidence of his client and his was also discounted.



In neither case was the Judge aware of what was in the experts reports. In my case he was not aware of the content of my supplementary report either.



The two experts who were criticised and whose evidence was dismissed were, as you say, both on the protocol committee.



Are there any other similarities?



I did not mean to ignore you point on the AB CP of course I have a view but I don’t want to interfere in a spirited debate just to offer an opinion that frankly, does not add much because if you have the facts you can and if you don’t you cannot.

On the assumption that this is a serious discussion, I thought you might appreciate knowing that in Egger, The court does not refer to it as a time impact analysis nor does it describe any methodology from which it could be infered that what I did was a time impact analysis.



In fact the court did not look at the analysis or my report. That is clear from the judgement.



In the case on costs that is referred to the court takes the unusual line in relation to the claimants case that my report did not follow the pleadings or the facts. Hitherto it has been held that an expert is not supposed to follow its clients pleadings but to advise the court and which of competing facts is adopted seem to be a bit of a lottery.



Incidentally, does anyone see any pattern in Egger and Great Eastern Hotel?

Uri and all…



As you mention Keith Pickavance, you may be aware that he did recently enter the fray on this subject at http://www.planningplanet.com/forum/forum_post.asp?fid=1&Cat=7&Top=8636. However, one must bear in mind that he is an ‘architect with a legal education’.



With KP being a vocal member of the drafting committee of the Protocol it is understandable that the Protocol and his book express similar opinions about Time Impact Analysis. As KP will know, in this instance, I could not have articulated the sentiments he makes about Time Impact Analysis better even if I had written them myself.



For TIA to be effective reliable base line programme is required and the impact analysis is only as good as the data put in and be supported by the pleadings or the evidence otherwise, as you suggest Uri, such inadequacies can generated a great deal of out of court time and expense and be a red herring of little value.



The criticisms of KP’s application of TIA continues in Skanska Construction UK Ltd. v Egger (Barony) Ltd. [2005] EWHC (http://www.bailii.org/ew/cases/EWHC/TCC/2005/284.htm), paragraphs 166 and 167.



Regards



David

David,



The Protocol on the published version of October 2002 clearly recommends the TIA to be used "whereever the circumstances permit" (section 3.2.11 page 44), and also "TIA is the most thorough method of analysis..." (section 4.16 page 48).



Keith Pickavance in his book (2000 edition) also seems to prefer TIA - "in the author’s view this is the only way in which the true effect of an event can be analysed..." (section 12.160 page 447).



The problem with TIA is that it is more expensive and more time consuming. However, when you take shortcuts, you might end up in the wrong destination...

Uri and all…



As I said in my message, I do think we need some decent definitions, the problem being one of interpretation and nuance.

I hope I didn’t give the wrong impression but in essence I agree with what you are saying; ‘Time Slice Analysis’ and ‘Windows Analysis’ are the same thing and ‘Time Impact Analysis’ and ‘Snap-Shot Analysis’. I’d prefer to drop the ‘Windows’ descriptor (it’s close association with Miscrosoft often leads to confusion) and similarly I’d prefer ‘Time Impact’ to the less formal ‘Snap-Shot’.

The techniques are broadly similar and, as you say TIA leads to a more refined analysis as it deals with individual events whereas TSA potentially deals with whatever number of events happen within the selected time period.



With regard to the Balfour Beatty case you can read the judgement here http://www.adjudication.co.uk/cases/bblambeth.htm. The methods were not listed in order of preference as far as I can tell, they were preceded by:



Before looking at the “final as-built programmes” exhibited by BB, Lambeth would make passing reference to the delay analysis methods most widely recognised and used: .



It is interesting that later in the Judgement the methods cited by the SCL Protocol are listed in order of preference:



1. Time Impact Analysis

2. Windows Analysis

3. Collapsed As-built Analysis

4. Impacted Plan Analysis



But this was taken from the November 2001, Consultation Version. Those familiar with the Protocol will know that in the final published version the types of analysis ‘recommended’ were:



1. As-planned v as-built

2. Impacted as-planned

3. Collapsed as-built

4. Time impact analysis



You will see that Windows Analysis has been replaced by As-planned v As-built. It would be useful to have some input from anyone who was intimately involved in the formulation of the Protocol. Does this mean that Time Slice/Windows Analyses is not a recommended method and has this come about as a result of deliberations between draft and final publication.



Regards



David

David,



TERMINOLOGY QUESTION.



I was confused by your last post (01 March). Is ’Time Slices’ analysis is the same as ’Windows Analysis’ or is it the same as ’Snap Shot’ or ’Time Impact’ analyses? To me the word ’Slice’ is more like a window than a point in time, as the term ’snap-shot’ suggests.



Correct me if I’m wrong, I think the difference between ’windows’ and ’snap shots’ is the RESOLUTION of the analysis - i.e. ’snap shots’ yield to more refined analysis, wheras ’windows’ is a more coarse one.



In this Balfour Beaty case that you are refering to, are the technique listed in an order of preference?



Thanx

The Great Eastern Hotel -v- John Laing Construction case raised some topical issues for planners. As has been correctly pointed out below, I was one of the delay analysis experts involved with the case. Sigfredo, Gerry and David ask some questions about the approach taken in the delay analysis, which I will answer.



The main question relates to the method of delay analysis used and the Judge’s statements in paragraphs 67 and 184.



In paragraph 67 the Judge wrote “Mr France used an impacted as planned programme analysis by which the project is analysed on a monthly basis to measure the impact of events as the project proceeded.” This is not strictly correct. For my main delay analysis work, I used what David helpfully describes below as the Windows Analysis. That is, for each month (or “window”) of the project, at dates co-inciding with the monthly progress reports, I looked at the progress position achieved and inputted that progress into the master programme to assess the delay that had occurred and what activities were on the changing critical path. I then investigated the reasons for that delay in that window, before moving on to the next monthly reporting period window.



In this way, I divided the project period into “windows”. The benefit of this method is that I put myself into the position of the people involved in the project at the time, looking at the situation at the time, with issues such as progress achieved, the design status and variations that had been instructed.



In paragraph 67 the Judge correctly describes the method used for the main part of the delay analysis by the defendant’s delay expert. “Mr Calekta for the main part proceeding retrospectively from an as built programme to determine the critical path and respective periods of delay and causes.”



What I have described above relates to the main part of the delay analysis, that is, what was the main critical path through the project, what were the delays to that critical path and what caused those delays.



Paragraph 184 is discussing a different aspect of the case. This concerned concurrent delays. The defendants argued that in addition to the main delays to the critical path through the project, there were other delays caused to concurrent activities, mainly caused by late design release. For this part of the case, Mr Caletka used the impacted as-planned method, in which he stated what the impact of that late design would have had on the original programme. As you will have read, the Judge didn’t like that approach because it didn’t take account of the actual events that had occurred on site.



Sigfedo asks if the Judge had a preference for an impacted as-planned programme than a retrospective as-built programme. I can see why Sigredo asks that question due to the wording in paragraph 67. No, I don’t believe that is the case as paragraph 184 makes clear, for the Judge didn’t seem to like the impacted as-planned method. He did seem to prefer a windows analysis over the retrospective as-built method.



I hope this clarifies the situation.



Gary France

Gerry and all...



This may be getting away from the original thread but I think we need some decent definitions here or we are all going to be confused with what is going on and what the Courts seem to think is acceptable or not.



I don’t think what is described at paragraph 67 is ‘Time Impact Analysis’ (although it could be a time impact analysis).



IMVHO ‘Time Impact Analysis’ is event orientated, the network is updated with progress just prior to, or at, the time an event occurs. This brings the programme up to date as far as current progress goes. Then the discrete event is simulated and it can be determined the effect of that particular event. This is described in the protocol (amongst other places).



I believe what is being described at paragraph 67, and Gary will have to confirm this, is ‘Timeslice Analysis’ (or ‘Windows Analysis’). This is time orientated inasmuch as the project is divided into timeslices (typically monthly) and the programme updated to reflect the current position at the beginning of the period. Then all the events that happen during the period are simulated. The effect on completion is a result of all the events simulated during the period. Not quite as clear cut as TIA (discussion on that point is for another thread I think) but it is useful for projects where there are masses of smaller type events (typically late information and instructions/variations type delays). Also it is generally less time consuming for a full TIA.



Balfour Beatty Construction Limited -v- The Mayor And Burgesses Of The London Borough Of Lambeth [2002] EWHC 597 (TCC) is a case often cited that gives some clues about what was considered to be the most widely recognised and used delay analysis methods:



(I) Time Impact Analysis (or “time slice” of “snapshot” analysis). This method is used to map out the impacts of particular delays at the point in time at which they occur permitting the discrete effects of individual events to be determined.



(II) Window analysis. For this method the programme is divided into consecutive time “windows” where the delay occurring in each window is analysed and attributed to the events occurring in that window.



(III) Collapsed as-built. This method is used so as to permit the effect of events to be “subtracted” from the as-built programme to determine what would have occurred but for those events.



(IV) Impacted plan where the original programme is taken as the basis of the delay calculation, and delay defaults are added into the programme to determine when the work should have finished as a result of those delays.

(V) Global assessment. This is not a proper or acceptable method to analyse delay.



I was a little confused by paragraph 184. It seems to give the impression that impacted as planned analysis was being carried out by Tony whereas I thought he was using an as built programme? Have I got the wrong end of the stick?



Regards



David

Hi Gerry,



thanks for the link, I’ve read some parts of it and I found it very interesting not to mention one of the more active PPers stood as an expert witness.



I just want to point out one portion of the court ruling for now. It seems to me the judge has a preference for an impacted as planned programme than a retrospective as built programme. I hope Mr. Gary France can enlighten us on this.



cheers,



Sigfred

Hi Gerry do you have a link to this.

Hi David,



Sorry for the delay in replying to your question about fairness, as it took a bit of reflection upon my career. But the answer I have come to is yes I believe I am, in most instances, although there has been a few times, I did not practice what I preach, but it was due to circumstances, where there no transparency existed. Helping contractors/subies, avoids problems in the future. If you explain things to them in the right way, it tends to obviate the same problems re-occuring. At present I am working on a NEC (New Engineering Contract) project, and find it most to my liking, as it is a give and take situation, and transparancy is the rule, but you still don’t wash your dirty laundry in public. The rule is if you mess up admit it, but in the correct forum.



Hope this answers your qustion.



Regards,



Philip

David,



A most interesting link.



Thank you



Chris Oggham

Dear David,



Thanks a lot for your valuable link.





Cheers!!!





Daya

David,



Thanx for the info on the Keane Associates paper on this old perennial!! (and I don’t mean me) ;-)



Cheers,



Stuart



www.rosmartin.com

Planeteers may like to know a paper on this subject has just been published by Keane Associates (www.keane-associates.com) at http://www.geg13.dial.pipex.com/Site/Content%20Pages/Updates/PDFs/Client%20Update%20-%20JAN%202005.pdf.



Regards



David

Philip



The activity may have been critical at the time. The point is that retrospective delay analysis is alive and kicking. Whilst I agree that delays should be notified at the time (and they mostly are) the fact remains that for various reasons there is often the need to find the ABCP.



However whilst I agree that entitlement should be dealt with as the project progresses and that best practices should be in place, the fact is that throughout the World, this isn’t always the case.



In the ’aftermath’ of a project after say two years of arguing (it must be remembered that just because a contractor notifies of a delay during the project, it doesn’t necessarily mean it will be agreed by the employer) the contractor decides to formalise his claim by proceeding to arbitration or litigation. How would you work out which events really did delay the completion of the project?



As far as your question are claims worthwhile? That obviously depends on the cost benefit analysis - most commercial organisations would say that it is worth spending 2 years and $1m fighting/defending a $10m claim if it is shown that he has a strong case!



Out of curiosity, as a fair minded individual; if you know one of your contractors has an entitlement but has not recognised it for himself at your weekly meeting - do you help him to identify this entitlement?



David

Hi Ron and David,



If I may step in again, and try and save the horse not only before it bolted, and is flogged to death, but before it is minced for sausages, to try and prove an ABCP is near impossible unless you have a well documented history, and what this history will show you is reasons for the delays.



Something can only be critical before it is about to happen, or during the time it is happening, once it it completed how can it be critical? This is the reason you should report a delay prior to it happening, or during the time it is happening, not after the project is happening. Where I come from, and I believe this is international contractual law, you have to notify of a possible delay as soon as possible, or within a specified period. So what is the point of trying to find an ABCP in the aftermath. If you have warned the client/managing contractor/contractor of such an event you have a right to a claim, if not you have not done your job as a planner. In every weekly meeting I am involved with, that is about 7 of them, involving contractors, they are asked if there are any potential or possible claims or any outstanding financial issues, we believe in fairness, so if the answer is NO they revoke their rights to any such issues, it is their job to report any problems, and mine to forward these, To my client/managing contractor. Should this fairness not be there, and the the matter is not minuted, they have the right to arbitration/litigation. So as a planner your job is to make sure, no matter where you sit in the tree, that you either be pro-active and give warnings at the right time, or ask the right questions. As somebody dealing with or consulting/advising on claims, you should make sure your employer/client, has these measures in place.

As somebody who believes in fairness, I think, you should also assist the contractors/subcontractors to ensure that they gave the right measures in place should they have an entitlement (Claim), and this could be done by auditing them on a regular basis and assisting them in ensuring they know the procedures. This can save any project a major amount on litigation or claim fees, and ensure everybody stays in business, as we should unless our practices are poor. Take a look at the cost of claims, and let me know if they are worthwhile. We should be handling claims in progress, not months/years after the fact.



An instance, I have to mention, in the recent past, happened on a plant in Mozambique, where the managing contractor stepped out of the fray, and six months later announced a n aditional profit of lets say $m40 and this was roughly the money lost by all the contractors. Try making a claim in Mozambique. The Managers all pocketed big bonuses nevertheless.



Back to the ABCP, I still think it is BBB (if anybody wants the meaning, contact me privately), any decent planner should have ensured there is a good costing system in place, in parrallel with planning, and this wiil be a better way of finding where the problems lay, and help to ensure better estimating and planning for future projects.



So "BASTA" to the so-called ABCP BBB.



Regards and thanks to All,



Philip J

Ron

Whilst I understand what you are saying, doesn’t this method simply mean that every activity will eventually become critical by virtue of the fact that the as-built float is used up? In my piling example, the activity was not critical in its entirity but your method would not reveal that, or would it?



At the end of the day, is the only way of determining the path for an planner to apply experience and common sense by reviewing what was being done in as much detail as possible, ie completion of piling in zone A allowed foundations to commence... and so on?



DW

David,



You can approximate the remaining duration of an activity on any given date the same way engineers always have – you interpolate between known points. You know the original duration and actual start or the remaining duration at the data date and you know the actual finish. Use a linear regression to estimate the remaining duration at any point between those two points.



Luckily, all of the work is done for you if you use an Expected Finish constraint. It is as simple as that.



Ron Winter.

Hello everyone,

Well this has been a long but interesting discussion. I thought I might jump in. First of all the answer to the ’does an as-built cp exist?’ is a definite yes. For example, if we take two simple activities, say piling and foundations, and evidence shows that the piling finished 6 weeks before founds - are we saying that the completion of the piling 6 weeks earlier was critical to the completion of the founds? The answer may be no, and the piling did not need to be finished until 2 weeks before the end of foundations, so there existed 4 weeks of float. The start of piling to the start of founds, however, probably was critical.



I have often seen Gerry’s --xx-x---xx--x-xxxx-x example in real life and as planners we know how to do manual forward & backward passes, but in the disjointed as-built example the normal method of calculating cp does not apply, does it? So is it acceptable for the planner to use his own experience & common sense to work out the critical path?



And Ron I agree with what you said about critical activites being different on a daily basis, but how do you look back at a particular day/week/month and work out what was critical at that time in the absence of progress data?



Like others I prefer ’windows’ analysis, however the progress data does not always exist and the --xx-x----xx info may only be available in a simple diary format - what then?

Mudassar,



I’d like to congratulate you on your concise message on this thread. I like your ’progressive critical path’ terminology.



I notice you only became a member of PP a few days ago, and look fowrard to your views on the ’claims’ forums in the future.



Roger

I found this topic to be a most interesting discussion. Ronald Winter’s post of 9/12/04 6:37 was the ‘Eureka’ post that summarised it for me.



I’m making these comments from a delay claims analysis perspective.



I believe there is such a thing as an As Built Critical Path. Otherwise I would be out of my job and might have to give back last few years of salary.



We might not want to call it an As Built CP although we constantly refer to it in delay claims analysis. I have used the term ‘Progressive Critical Path’ in a number of reports I have worked on as it was based on the analysis of the logically linked status programmes issued by the Contractor. I’ll use the term Progressive CP for now; seems like a bread winner to me.



The Progressive CP basically shows which task is (I’ll come back to this) critical on any given day during the duration of the project and yes, it is subjective and depends on the skill, experience of the planning analyst, as built information and contemporary records available to and relied upon by the analyst.



Theoretically, if I have a crystal ball that allows me to see which task is critical on any given day, as far as I am concerned that is the task that needs to be progressed that day. If there is no progress on that task on that day it WILL delay the completion of the project by 1 day.



For a claims analyst, the Contractor’s programme (a CPM network) is the best starting point for such a crystal ball (or insight) into a project. It is a readily available source of the Contractor’s methodology for when and how he intends to complete the project. The monthly status programmes provide a snapshot of what the Contractor believes is critical on that status date (I am assuming that the Contract Administrator/ Superintendent is doing its job and reviewing the progress information entered and the forecast for the remainder of the works). We can use that information and using rudimentary mathematics and CPM logic in the programmes (labour intensive as it may be), to determine how individual tasks slipped (or lost float and became critical) during any two status programmes. This provides us with what IS critical on any given day between those two status dates. The smaller the interval between any two status programmes, the more reliable the resulting Progressive CP for that period.



Don’t worry that’s just the first attempt. We can and in most instances will definitely need to refine it through contemporary records (what was reasonably known by the Contractor on that date) and as built information (as suggested by Roger Gibson in his post of 5/12/04 12:14). That’s where the experience of the planning analyst is most important and the eventual Expert Evidence, if any. It also depends on the quality of the status programmes and the progress information entered in those programmes. It also depends on how much time and money is to be spent on the exercise.



Repeat this process on a succession of status programmes. After we have determined that set of tasks that was (or should we now say IS) critical for each day of the project’s life and combine it and overlay it on an As Built Schedule; you get a Progressive Critical Path (see Ronald Winter’s post of 9/12/04 6:37).



Using the bottom down approach, the fine tuning of the Progressive CP can be done to the umpteenth degree for the period/s during which the delay/s are claimed. If the delay lies on the As Built Critical Path, it was critical.



And yes, I agree with David Barry (post of 5/1/05 12:34) that the ‘connection between as-built critical path activities does not have to be physical, logical, resource driven or otherwise – the connection is simply that it was [of course looking back] critical at the time…”. The connection only tells us when an activity ceased to be critical and the critical path shifted to another task.



I can’t wait to check out the website/ software that Ronald Winter mentioned in his email of the 7/12/04 2:42. This could be an excellent tool for a Progressive CP analysis using the status programmes. At least it might take a lot of the manual calculations out of the analysis. Seems like I am using the CPM for similar purposes; except that I start from day 1 and move forward to the end of the project through successive statuses.



Ron, can I get a demo version 



MR

Uri, You’ve answered your own question; only by retrospective analysis.





Roger Gibson

Gerry,



Quote from you post: ’However, if the critical path did not switch between different chains of activities - then it could be accurate to describe it as the as-built-critical-path’.



Once the project is finished, how do you know if the CP switched during the project without retrospective analysis? it could have gone somewhere else, and later return to it’s original path. Would an ABCP be obtainable then?



Anyway, could you help me with the following question:



Assuming the ABCP does not exist, and that the Contract allows for ’actual delays to the date for PC’ only,how do you know which delay effected this actual date?

Gerry, Gary, David, Roger, Stuart and all,



This has been the longest and I think the most interesting thread we had on our claims forum sofar. It seems to me that now the subject is more or less exhausted.



I would love to see a paper summerising in a well structured way all the ideas and opinions brought forward under this thread.



Do you know of somebody, perhaps someone who needs a paper for the PEO, or a student that will take up such challenge?

Philip

Looking forward yes, Looking backwards no.

David

Hi David,



I started and learnt planning before computor aided planning existed, however, planning cannot be done without logic, whether by compütor or manually on paper. It is this logic that determines the criticality of activities, therefore you cannot have a critical path without continuous logic.



Regards



Philip

Razi,



The answer you seek is to do with planning software, not whether an ABCP exists! When did planning become solely a computer excercise?



The Greeks did planning when they were building the Acropolis, and I submit (provided the records were available) a decent planner could establish what the actual crtical path was throughout the job!



I think my 2 cents has grown to a dollar making the same point, so I’ll leave it to others for a while!



Regards

David

I hold the view a critical path can only exist in the as build stage before that it is only a projected/forecast critical path.





Cheers

Hi David



As per your logic "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" than many or all activities could fullfill this criteria in isolation no doubt, but untill unless you do not connect them how you could you establish path leave critical or not.



I hold the view ABCP do not exist.



Regards