Critical Path Method/Crashing Definition

[exam cisa]

CPM:

 

The critical path is the longest duration path through the network diagram and determines the shortest path to complete the project,

 

Can someone help me understand this.?

 

 

Crashing:

 

This technique involves making cost and schedule trade offs to determine how to compress the schedule the most for the least incremental cost while maintaining project scope.

 

Crashing by definition will always cause increased costs.

 

I see some contracting statements. Please clarify these 2 terms for me.

 

Thanks

[Srini Asadi]

On Wed, Jun 23, 2010 at 6:42 PM, Srini Asadi <srini...@gmail.com> wrote:

Let me attempt to explain.

CPM is longest duration path : Though all other paths also connected from ‘Start’ to ‘End’, they are lesser duration than CP. Means You may reach the ‘END’ point by that path but it is not the actual end of the project since some activities (in other paths ex. CP) will be still in progress. So, only by duration of CPM path, all the other project activities also will be completed. So, it is considered as the longest of all the Paths.

Shortest path to complete the Project means by the time these critical activities are over all other non critical activities are also gets completed. So, the project completion will at least take this much duration. Of course you can crash, fast track the CPM activities also. But it is more risky and effect other activities leads, lags etc. so the complete Critical Path may get changed or you may get multiple critical paths, means more risky activities. 

Crashing : Pl. remember our school days maths, If one man takes 10 days to complete one activity, 5 men will take how many days? As per that they will take 2 days.

Crashing is same as that. You apply more resources to get the activity completed faster. More resources means more costly (may be due to demand), more efforts to PM (to get these resources even these procurements cost may also gets added some times). Means to get the same scope of work completed, PM is increasing cost to get the schedule compressed. Means, in general, cost and schedule are inversely proportional.

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Thanks & Regards,
Srini

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Thanks & Regards,
Srini

[Srini Asadi]

Let me attempt to explain.

CPM is longest duration path : Though all other paths also connected from ‘Start’ to ‘End’, they are lesser duration than CP. Means You may reach the ‘END’ point by that path but it is not the actual end of the project since some activities (in other paths ex. CP) will be still in progress. So, only by duration of CPM path, all the other project activities also will be completed. So, it is considered as the longest of all the Paths.

Shortest path to complete the Project means by the time these critical activities are over all other non critical activities are also gets completed. So, the project completion will at least take this much duration. Of course you can crash, fast track the CPM activities also. But it is more risky and effect other activities leads, lags etc. so the complete Critical Path may get changed or you may get multiple critical paths, means more risky activities. 

Crashing : Pl. remember our school days maths, If one man takes 10 days to complete one activity, 5 men will take how many days? As per that they will take 2 days.

Crashing is same as that. You apply more resources to get the activity completed faster. More resources means more costly (may be due to demand), more efforts to PM (to get these resources even these procurements cost may also gets added some times). Means to get the same scope of work completed, PM is increasing cost to get the schedule compressed. Means, in general, cost and schedule are inversely proportional.

On Tue, Jun 22, 2010 at 2:25 AM, exam cisa <exam...@gmail.com> wrote:

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[SM]

Critical Path:

PMBOK Glossary says:

"Generally, but not always, the sequence of schedule activities that determines the duration of the project.  It is the longest path through the project."

The project cannot be considered complete until all of its activities are finished.  While some activities can be performed simultaneously, many have to be done sequentially since they depend upon the completion of a previous activity.  The earliest the project can be completed is when the entire path of these sequenced activities has been completed.

Crashing:

A technique to compress (reduce) the schedule by applying additional resources (this typically means adding more people) to activities on the critical path.  Adding resources costs money, so crashing always has a cost consequence.  This additional cost has to be weighed against the benefit gained from reducing the schedule.

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[exam cisa]

Hi Srini

 

Could you also explain me the concept of float, positive negative float and free float, project float and total float.

 

Critical path has zero or negative float why? please explain.

 

You explain it very well. thanks

 

thanks so much