Critical Path

thanks

i have sent at ur id

bilal



Yes,to avoid misunderstandings.



[email protected]

soory i did not understand exactly....



but i think u meant.... like



i bars(buttons) i have marked to displak critical remaining work as critical in red colour and filter selected is that by deafult "normal and critical"



so i dont think there is problem with filter





can i send u eht prog as mail.....to check ....if u dont mind..

I assume your mistake is within the filter.

What does mean: "not showing them as critical activity". How did you explain this to your pc?

activity whoes total float is zero i consider it will be critical activity so there are activities in layout whoes tota float the program is showing as zero but not showing them as critical activity and when i run the filter of critical activities they dont come in it

Bilal

How do you show critical activities?

How do you identify activities being critical?



Dieter

Still doesnt Work..... can there be a a problem with the bars layout/colour and customization.....?

Bilal

Check please: "F9" --> Button "Options" --> Define critical activities as: mark "total float" and enter 0,00

Then it should work.



Regards

Dieter

Dear Dieter



I have checked that even ...the total float is exactly zero

and yes, these activities dont have any type of constrain on them even..... i m really losing my mind

Bilal



1. Check for mandatory constraints. Those activities by definition have FF=TF=0 but aren’t critical.

2. Edit --> User Preferences --> Time Units --> change decimals for duration to 2. You’ll see e.g. 0.02 and no longer 0 - and that’s not zero.



Hope that helps.

Dieter

Dear Samer



?I have checked these activities are linked .. and more over free float and total float is zero but still the same they are not shown as critical.......so whay shall i do

Dear Bilal,

Can you check the linking between activities? Maybe they are not linked.



Best,



Samer

i have activities with total float/free float zero but they are not being shown as critical activities what can be the reason...I am working in P6



i have checked the rule of critical is same as less or equal to zero total float

Hi Anoon,

Yes, I quite agree with you - and it would be marvellous if "they" would allow it. However, what we must remember is the element of psychology and human expectation that lies behind any of the decisions that are made. These perceptions and expectation originate at the start of the project.



Let’s take two extreme examples of the same project, but the programme visibility is at the two opposite ends of the spectrum e.g. a 10-line summary and a 100-line summary.



10-Line Summary: The client will be looking to the contractor to complete the activities by the end-date shown on each one of those 10 summary lines. Essentially, in the mind of the client, each individual summary line becomes a mini-project. Therefore, it can be said that each mini-project will have its own critical-path. It is not an un-natural expectation that, if you complete each summary as shown on the programme, then you will instil confidence in achieving the overall project end-date. This confidence is derived by virtue of historical trend in the contractor having adhered to all previous summary dates. Technically, however, all of your critical activities may reside under just 6 of those summary-lines.



100-Line Summary: The client now perceives that you have 100 mini-projects – therefore 100 critical-paths. However, the programme may possibly have enough float to be late on 75 of those summary lines without affecting the overall project end-date. Regardless: if you show significant delays on the first 50 summary-lines, the client isn’t going to be very impressed and won’t be in the mood to accept your explanation that, in reality, the overall project end-date hasn’t been affected. This is because your historical trend has shown that, to date, you haven’t adhered to any of the planned dates – so why should the client believe that the overall project end-date is going to be achieved.



The above is just a very, very simple example. However, as soon as you show them the programme – especially to a non-specialist programmer – you have formulated a set of expectations in their mind.



This is what you must consider:

1) The more summary-lines that the client sees, the more “projects-within-projects” will be assumed. Therefore, as “each project has a critical-path”, it will be assumed that there are as many critical-paths as there are summaries. This has no mathematical basis when considering the conventional definition of a project’s true critical-path.



2) The more summary lines that the client sees, the less flexibility there is to re-sequence activities without affecting summary-line end-dates. Therefore, you have an increased probability of showing that, in the mind of the client, you are “running late” – thus inducing panic into the client. However, this “lateness” is entirely misleading. This is because the more summary-lines there are, the smaller the statistical probability of a “critical activity” residing under each summary task. In reality, therefore, you can happily “run late” on a large proportion of your activities with no effect on the project’s end-date.



3) If you take point 2 to its logical conclusion, and show every task on the programme, then you could be late on maybe 90% of those tasks and still not affect the project end-date. Yet if you sat there and told the client that you’re going to delay 90% of your tasks – and you’re still going to achieve the end-date, he’s going to think that you’re insane.



This is always the problem when discussing programmes with a non-specialist programmer – and especially if he is under pressure. All he sees is the raw data (the progress report) and if that progress report says that 50% of his activities are late - “but don’t worry, it’s not critical” he’s not apt to listen to anyone, regardless of how much you try to convince him.



Cheers.



James.

“All he sees is the raw data (the progress report) and if that progress report says that 50% of his activities are late - “but don’t worry, it’s not critical” he’s not apt to listen to anyone, regardless of how much you try to convince him.”



And rightly so, planners can fool themselves by staring too hard on the Critical Path. Other consideration should not be forgotten, such as overall performance.



Regards,

Larry

Precisely, Larry - and that’s why EV was born. So here we go again....



James.

James,



I still believe that the Planner should be the one to determine the critical path. A good planner can educate if not brainwash the customer..

Hi Anoon,



The real critical path is determined by Politics and Money. Established theory has very little influence when a customer or a boss starts shouting.



I can quote a number of examples where equipment should not or did not need to have been delivered - but the politics and money overwhelmed any ideas of common-sense.



James. :-(

Hi All,



What really determines the critical path? Is it the theory established or is there something else?

Well thanks Andrew, Hashim & Ahmed

Karim,



It doesn’t matter if there are 100 critical paths. If one of them delays the completion date (and it’s an Employer liability) then you will get an EoT.



An EoT to completion is awarded for an Employer event that moves the contractual completion date. Your job may be split into 10 "separate" jobs but the contract is for ALL the separate jobs as a whole.



For sectional completion the critcal path of each section will be relevant only to each sectional completion date unless of course the sectional completion date moves beyond the overall completion date at which point it will be relevant to both sectional and overall completion.



Multiple critical paths aren’t a problem even if you project isn’t split up and everything is dependant on everything else. It just shows you that there are a number of different construction activity sequences on the project that may affect the completion date and should be managed accordingly. You’ll normally find that multiple critical paths don’t stay multiple for long.

Hashim,



Reg. “for me its not a critical path”.



I might be wrong, but I think the longest path to a milestone is the critical path, independent to the total float. See #2.



Regards,

Larry

Hashim,



Reg #3: When I think in theories, I find it helpful to think extreme spectrums. What if the schedule only has a single task? What if the schedule have X number of tasks, and all tasks have the same start date and same duration, and all tasks required to be done for the planned milestone. If that is the case, then each task becomes a critical activity and becomes a critical path.



Reg #5: You are right, I’m wrong on this one. I ought to have said Fixed milestone rather than Planned Milestone. The total float in a critical path is always 0 in relation to a Planned milestone. However, the total float in a critical path can be any number against a Fixed milestone.



Thanks,

Larry

Hi Guys,



This debate follows many others in that we are now starting to change the "official" definition of Critical Path in order to accommodate the reality of our day-to-day project management and planning roles. This is where the fun begins!!!



We currently have a scenario where our programme showed the purchase of a robot. This was based on a baseline programme that had not been optimised and was essentially forced upon us. However, there is no particular reason why the purchase could not have been delayed another 6 months - as it was not on the critical path. In the event, the client decided to declare such a purchase as one of his PBIs (Performance Based Incentives) in order to get himself an additional financial bonus. Because of this, you could argue that we now have a sub-project within the overall project - therefore two "critical paths". This now confuses the issue at any time when we use the term "critical path". We have to be very specific and say the "critical path to achieving milestone X...."



The more often and more detailed the client programme levels are reported, the more "critical paths" a project will have. This becomes especially true if the client also has a financial incentive to achieve a particular milestone - even though delaying it will not affect the overall project end-date.



Overall, the contractor will be best served by reporting at the highest summary-level possible. This will give him the greatest flexibility to accelerate or delay activities according to evolving conditions - without causing panic and worry in the client. Ideally, the client should be interested in only one thing - and that is the project end-date. Only then can we begin to return to the original or official definition of the term "critical-path". Unfortunately, life is never as simple as that, and I’ve no doubt that we will never return to it. As a result, we will have to educate them and ensure that, when they use the word "critical path", they must be very specific about the event that they are discussing.



James :-)

I believe in case if you want to make a EOT you need to look to all the activities first and define which activities will cause the EOT because some times you will have activities that are not on the critical path ( in the base line ) but become critical afterwards .

And I can’t see any reason why the engineer doesn’t approve having many critical paths in 1 schedule as long as you have all supporting documents \ proves that what you have put the correct logic into the schedule



regards

Hi,



So if there are more than 1 critical path in the schedule (which u will deal with them as separate projects), then if u are planning to make an EOT which critical path u will use in this (each seprate project alone? or the wohle schedule as 1 unit), moreover will the Engineer approve having many critical paths in 1 schedule?

Planners,



Here is some food for thought.



1. In planning, the longest path in a schedule is usually referred to as The ‘Critical Path’.

2. In general, a Critical Path is a structured activity sequence with the longest duration to a Planned milestone.

3. Theoretically, in the extreme spectrum, there can be as many critical paths in a schedule as the total number of tasks.

4. There is a minimum of 1 critical path to each Planned milestone.

5. All critical paths do not necessary have the same total float if the schedules have more than one Planned milestone.

6. All critical paths must have the same total float if the schedules have only one Planned milestone.



Regards,

Larry

Hello all,



I never count critcal path as 1,2... For me critical path is only a collection of critical activity.



I would like to establsih critical path based on contractual milestones (especially LD milestones)rather than the overall completion date of the project.



For example milestone "ready for production equipment move-in & hook-up", and after that we need hook up, testing , trial run, documentation, training..., these may takes quite long time and lead to the completion of the project.



and for degree of criticaity, IMO cost is the key point not the total float,a milestone with 5days TF, fail to achieve will cost 1000$, a milestone with 0day TF,but fail will cost 100$, which is critical?

Hi Ashraf Alawady



Degree of criticality will depend on the total float on the updated programme. Normally the activites with total float less than 1 are considered critiacal.

The activities with zero float are at the verge. Any further delay with certainly push your early finish date and correspondingly your total float will enter -ve .

thus the more negative an activity gets ie (-5 means 5 days delay -10 means 10 days delay)



The degree of criticaity is upto you to decide if this is what you were asking.



Like, if an activity with base line float of say 10 gets its total float eaten away slowly on each updation and reaches 0 and it becomes critical then; but u were too late to detect this. Insuch a case you could put "critical activites to have float less than 5 or something like that depending on your experience and observation of the trend. this would help you to detect activities which are about to touch 0 in advance and thus expedite and do the needfulintime. You could also



just leave the critical activities as it is have float <1

and put a filter on activites wih totalfloat less than 5 or 7. coz when u present an update if activities with float >1 show critical it may sound hard to digest unless you tell him what u were actually trying to do.....



Hope this is what you wre looking for





Regards

Sherif A Aziz

I agree with you Hashim Mahmoud . You have rightly spoken the situation I have encountered recently. When two works or lets say subprojects with same duration start parallel and haeve the same finish date then we certainly will have two critical paths. And yes as a planner you are supposed to show the critical activities as they are.



I think it is really reasonable to to show more than one critical path in your updates aswell. I agree with you. There is no need to take the longest path as the critical path.

But for simplifying the situation at a glance we could suggest the longest path to be critical on the baseline unil we have started updating the progress. Once we have started updating the progress I agree there is no need to stick to the longest path and after all this is a tool to guide ythe user and the standards have thus to be set by the user according to his needs.



That was really good Hashim Mahmoud

I believe you can have more than one critical path also in following cases:-

1- if you have intermediate milestone to deliver certain part of the project by a defined date in some cases the may push some activities to be critical even if those activities don’t affect the overall project duration . some times those intermediate completion dates are more important than the overall project completion date ( which determine the critical path ).

The second case if you have 2 different trades affecting your project completion date

An example for this could be.

The final finishes for a building in Dubai for example might need a control environment to carry out your final paint and wood works ( doors \ wardrobes) this will require.

: a ) MEP installations to be completed to certain extent .

b curtain walls glazing.

c external MEP installations ( main power \ chilled water Etc ) which even might come under another project \ contract .

for me there are 3 critical paths in the above example

regards

Excellent, Shareef

You have given good clarification which is supprting my opinion that we can have more than one critical path for one project.

But still i did not get any clarification regarding the dgree of criticality .

REGADS

Excellent, Shareef

You have given good clarification which is supprting my opinion that we can have more than one critical path for one project.

But still i did not get any clarification regarding the dgree of criticality .

REGADS

Hi all



Critical path like what was mentioned earlier is the path which is critical which means a delay of the activities on this path will certainly delay the project.



The statement of resources driving the critical path arises only if you have assigned limits for your resources.



Yes the critical path is generated by the system itself based on the beauty of ur linking logic.





Normally the activities which have zero total float for the crtical path and there is an optiion in P3 for you to select the minimum float u need for the system to consider the activity as critical or not .

ie if you go to - Tools-> options-> critical activities you can set the critical activity selection criteria.



But like what was said b4 normally we set the longest path as the critical path coz there can be more than 1 critical path in the programme . It depends on the interdependece of the different works taking place coz sometimes you might have works in different areas which totally have no relation among themselves which naturally means you can have more than one critical path.

And like i said the normaly way is to take the longest path as the critical path coz this will shift the critical path incase any other path becomes the longest critical path after you start updation.



Cheers

Sherif A Aziz

Hi,



There is only 1 crtical path in the project, The Primavera project management application employs the Critical Path

Method (CPM) scheduling technique to calculate project schedules. CPM uses activity durations and relationships between activities to calculate project dates.



This process is performed in two phases or “passes” over the

activities in a project.



The first pass or “forward pass” calculates the early start and early finish dates for each activity, based on the start or finish dates of predecessoractivities as well as the duration of the activity itself.



The second pass or “backward pass” calculates the late start and late finish dates for each activity, based on the start or finish dates of successor activities as well as the duration of the activity itself.



The free float and total float for each activity are recalculated.



in Risk, Simulation uses a representation or model of a system to analyze the behavior or performance of the system. The most common form of simulation on a project is schedule simulation using the project network as the model of the project.

Most schedule simulations are based on some form of Monte Carlo analysis. This technique, adapted from general management, “performs” the project many times

to provide a statistical distribution of the calculated results (which can produce more than 1 critical path).



most of the above were taken from Pmbook guides and P5 manual.

hi, In my experience one project has only one critcal path. If you have different structures having the links each other with different finishe dates, last structure finish date is the project completion date. In this case you have to provide finish constraints for individual structure so that u will have critical for each structure.

Hi,Hashim

since you have agreed with me that we can get more than one critical path in one project, can you tell me some useful information about the degree of criticality.

Thanks

Hi,Hashim

In many cases when we did a planning for some projects we found more than one critical path.



in the time being , we have a running project for roads and infrastructure which consistes of constructions of 4 separate junctions in different locations and the total duration of the project is very limited so we have to start the construction in all the junctions in the same time with a separate resources for each junction.



after completing the programme we found that we have 4 critical paths in our project.

I hope that i could explained the case which we face it practically due to the particular nature of some projcts.

Regads

plese be informed that:-

*The critical path is connecting the critical activities in a project.

*The critical activities are the activities have total float equal zero.

*In one project we may have many critical pathes but we are considering the longest critical path in which any delays happend in any of the critical activities includded in that path will lead to delay in the completion date of the project.

*We are not making the critical path but the critical path will be created automaticly after building the structure of the project programme correctly and by following the correct logic, sequances, relations,daily productivity.................etc.