A schedule with high probabilities of meeting time and cost targets is better than a schedule with low probabilities of meeting time and cost targets.
How it is done is well documented and is very simple; make a plan that targets for completion completion that is earlier than contractual date. It shall be a feasible plan, with enough resources to make it but as we all know, there will be no magic and even this one will be delayed, but hopefully will still make it on time. Schedules with no buffer are doomed for failure.
We know things usually starting with the letter "S" do happen.
The management of schedules considering the non deterministic nature of activity duration [production rates], the effect of what is known as Parkinson's Law and Student Syndrome are well known by some schedulers but not all, judging from the comments of a few.
There are advocates for different approaches to the non deterministic nature of schedules but essentially they all target for an optimistic schedule whose duration is less than the contractual.
Some might argue Monte Carlo is the best but I believe it will depend on the schedule requirements, for simple schedules a single deterministic schedule is ok, for other schedules a two schedules approach is ok while for others full Monte Carlo and/or three schedule approaches are better.
At the end no matter what, the deterministic target dates will prevail in contractual terms, even when usually are better managed using non-deterministic approach than using "old School" deterministic approach.
I would dare to say the traditional deterministic approach that consumes all contractual duration is the worst in most occasions.
USUALLY DETERMINISTIC APPROACH IS A LIE - NO MATTER IF YOU UNDERSTAND WHAT IT MEANS OR NOT
The key is to getting a Baseline with high probabilities of success, theoretical but better than deterministic. A model with enough buffer or margin. The theory for delay analysis are still the same, any projected delay on Target Schedule [schedule with margin] early dates represent a delay. But when mathematically correct probabilistic model is not accepted then the Contractor has no other option than to keep two parallel versions to satisfy the whims of others.
Anyway it is naive to believe either the Target with some margin or a Deterministic Target will be fixed in time and will happen as if written in stone. It is a matter of a better approach in the quest for meeting contract milestones.
I agree 100% with Dieter - 2 schedules at best means on is a lie. And if you are proven to be dishonest in one place, no one will believe you anywhere.
Member for
24 years 9 months
Member for24 years9 months
Submitted by Vladimir Liberzon on Wed, 2014-10-22 16:34
Evgeny, I expect that the reasons may be different in different countries.
General Contractor manages overall project where subcontractors are responsible for subprojects. These subprojects may be linked and delays in one project may cause delays in another. Detailed schedule helps to notice potential problems ASAP and then try to find the reason. One of potential reasons is the lack of required resources. That is why subcontractors shall submit resource loaded schedule. In this case it is easy to compare the number of workers that should work with actual number of subcontractor workers on site. If required number is larger than actual General Contractor may insist on adding subcontractor workforce.
Revising subcontractor schedule it is possible to understand how the subcontractor plans to achive project milestones. In other case their achievement is not reliable. You may trust but it is risky,
Member for
16 years 3 months
Member for16 years4 months
Submitted by Zoltan Palffy on Wed, 2014-10-22 13:49
Sorry, that I intervene in this construction schedule dialogue.
But question is: would it not be a right thing to manage subcontractors based on the milestones and not on the detailed schedule and letting them to determine themselves on how they reach these milestone as well as on how much contingency they set for themselves?
If one requests an internal detailed schedule from contractor, this sort of implies, that subcontractor is not trusted to do his job correctly and also that the contracting authority goes into the business of micromanagement of subcontractor, which is not exactly the idea of having subcontractor in the 1st place, because then you treat subcontractor as the part of your internal organisation.
Or, am I missing something?
Regards.
Evgeny
Member for
24 years 9 months
Member for24 years9 months
Submitted by Vladimir Liberzon on Tue, 2014-10-21 14:42
Aaron, this is the usual practice and is reasonable. Contractor shall have contingency reserves to be able to finish on time. So his internal schedule shall be tighter. His reserve may be called buffer but it is created for his internal schedule risks and it is natural that he does not want that this reserve will be used by the Client. Actually there are three schedules that are used by General Contractor:
Contract schedule that includes both contingency (for known unknowns) and management (for unknown unknowns) reserves of General Contractor,
General Contractor project team schedule that includes only contingency reserves,
Subcontractor and project work force schedule that does not consider General Contractor risks (optimistic).
First 'I absolutely don't like multiple schedules with same content but different dates and durations for the same project. Big risk for mistakes, maybe the client will feel betrayed, it's not honest.
Early finish earlier than contractual finish: Why not include activities "Buffer" at those places where you'll need it? In my opinion this will avoid a discussion on EOT claims due to the differeence between early finish and contractual finish. EOT may happen later.
Member for
21 years 8 monthsA schedule with high
A schedule with high probabilities of meeting time and cost targets is better than a schedule with low probabilities of meeting time and cost targets.
How it is done is well documented and is very simple; make a plan that targets for completion completion that is earlier than contractual date. It shall be a feasible plan, with enough resources to make it but as we all know, there will be no magic and even this one will be delayed, but hopefully will still make it on time. Schedules with no buffer are doomed for failure.
We know things usually starting with the letter "S" do happen.
Google for:
Theory of Constraints
Monte Carlo
Schedule Margin
Student Syndrome & Parkinson Law
Member for
19 years 10 monthsHi Rafael"It is a matter of a
Hi Rafael
"It is a matter of a better approach in the quest for meeting contract milestones."
What is better than a fully resource modelled schedule that closes the Scope Money Time triangle?
Best regards
Mike Testro
Member for
21 years 8 monthsThe management of schedules
The management of schedules considering the non deterministic nature of activity duration [production rates], the effect of what is known as Parkinson's Law and Student Syndrome are well known by some schedulers but not all, judging from the comments of a few.
There are advocates for different approaches to the non deterministic nature of schedules but essentially they all target for an optimistic schedule whose duration is less than the contractual.
Some might argue Monte Carlo is the best but I believe it will depend on the schedule requirements, for simple schedules a single deterministic schedule is ok, for other schedules a two schedules approach is ok while for others full Monte Carlo and/or three schedule approaches are better.
At the end no matter what, the deterministic target dates will prevail in contractual terms, even when usually are better managed using non-deterministic approach than using "old School" deterministic approach.
I would dare to say the traditional deterministic approach that consumes all contractual duration is the worst in most occasions.
USUALLY DETERMINISTIC APPROACH IS A LIE - NO MATTER IF YOU UNDERSTAND WHAT IT MEANS OR NOT
The key is to getting a Baseline with high probabilities of success, theoretical but better than deterministic. A model with enough buffer or margin. The theory for delay analysis are still the same, any projected delay on Target Schedule [schedule with margin] early dates represent a delay. But when mathematically correct probabilistic model is not accepted then the Contractor has no other option than to keep two parallel versions to satisfy the whims of others.
Anyway it is naive to believe either the Target with some margin or a Deterministic Target will be fixed in time and will happen as if written in stone. It is a matter of a better approach in the quest for meeting contract milestones.
Member for
19 years 10 monthsHi PatrickIn my opinion there
Hi Patrick
In my opinion there is nothing wrong with a contractor having two programmes for the same job.
One with a set of shorter durations for sub-contractors - set on a 10 hr day and another with the full duration - 8hr day - for the employer.
It is not a lie when the contractor and the sub-contractor sign up for there own deal independent of the main contract.
The trick is not to get the two mixed up when reporting progress.
Best regards
Mike Testro
Member for
24 years 9 monthsI agree 100% with Dieter - 2
I agree 100% with Dieter - 2 schedules at best means on is a lie. And if you are proven to be dishonest in one place, no one will believe you anywhere.
Member for
24 years 9 monthsEvgeny, I expect that the
Evgeny, I expect that the reasons may be different in different countries.
General Contractor manages overall project where subcontractors are responsible for subprojects. These subprojects may be linked and delays in one project may cause delays in another. Detailed schedule helps to notice potential problems ASAP and then try to find the reason. One of potential reasons is the lack of required resources. That is why subcontractors shall submit resource loaded schedule. In this case it is easy to compare the number of workers that should work with actual number of subcontractor workers on site. If required number is larger than actual General Contractor may insist on adding subcontractor workforce.
Revising subcontractor schedule it is possible to understand how the subcontractor plans to achive project milestones. In other case their achievement is not reliable. You may trust but it is risky,
Member for
16 years 3 monthsyou posted it on a forum in
you posted it on a forum in linked-in so please look at your post there.
Member for
17 years 9 monthsSorry, that I intervene in
Sorry, that I intervene in this construction schedule dialogue.
But question is: would it not be a right thing to manage subcontractors based on the milestones and not on the detailed schedule and letting them to determine themselves on how they reach these milestone as well as on how much contingency they set for themselves?
If one requests an internal detailed schedule from contractor, this sort of implies, that subcontractor is not trusted to do his job correctly and also that the contracting authority goes into the business of micromanagement of subcontractor, which is not exactly the idea of having subcontractor in the 1st place, because then you treat subcontractor as the part of your internal organisation.
Or, am I missing something?
Regards.
Evgeny
Member for
24 years 9 monthsAaron, this is the usual
Aaron, this is the usual practice and is reasonable. Contractor shall have contingency reserves to be able to finish on time. So his internal schedule shall be tighter. His reserve may be called buffer but it is created for his internal schedule risks and it is natural that he does not want that this reserve will be used by the Client. Actually there are three schedules that are used by General Contractor:
Contract schedule that includes both contingency (for known unknowns) and management (for unknown unknowns) reserves of General Contractor,
General Contractor project team schedule that includes only contingency reserves,
Subcontractor and project work force schedule that does not consider General Contractor risks (optimistic).
Member for
11 years 11 monthsZoltan, That is great you
Zoltan,
That is great you answered it. Could you provide a link to the forum?
Member for
16 years 3 monthsalready answered this in the
already answered this in the other forum
Member for
18 years 9 monthsHi Aaron First 'I absolutely
Hi Aaron
First 'I absolutely don't like multiple schedules with same content but different dates and durations for the same project. Big risk for mistakes, maybe the client will feel betrayed, it's not honest.
Early finish earlier than contractual finish: Why not include activities "Buffer" at those places where you'll need it? In my opinion this will avoid a discussion on EOT claims due to the differeence between early finish and contractual finish. EOT may happen later.
Regards
Dieter