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Resource Critical path

15 replies [Last post]
Thu, 2004-12-02 07:22
Gerry Morgan
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Hi There

It seems to me this is one of the most important things when producing a schedule, but I do not see any automated way of actually seeing the Resource Critical Path from within MS Project 2003.

Am i missing something here and if not what would be the best way to view this? other than going through the whole scedule task by task

Thanks
Gerry.
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Replies

Tue, 2004-12-28 04:24
#1
A. Faisal Shaazi
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Dear list,

In my experience (for most schedules at least), the identified Critical Chain is not a unique solution. Thus different CC software may yield distinctly different critical chains even from the same schedule.

There are some optimizations that can be done, e.g. minimize schedule length, longer duration tasks earlier/later, etc. I agree with Larry Leach when he talks about a "good enough concept". He says (Critical Chain Project Management, p153), "No proven algorithm exists for resource leveling to ensure an optimum schedule".

In some cases, the resource leveling implementation in MS Project cannot create a resource-leveled schedule suitable for the creation of a critical chain schedule. I’m not sure when MS will have this fixed.

Cheers and have a peaceful / safe new year.

A. Faisal Shaazi, PMP
Principal Consultant
Unified Vision - Makers of Critical Chain Software

Mobile:+6012.6080.745
Fax:+603.89484829
E-Mail:ashaazi@unifiedvision.com
Visit us at <>
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Thu, 2004-12-09 16:55
#2
Vladimir Liberzon
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OK. MS Project Example:
2 resources A and B
Activity 1, Duration 20 days, Resource A
Activity 2, Duration 20 days, Resource B
Activity 3, Duration 1 day, Resource A
Activity 4, Duration 20 days, Resource B
Activity 5 - Finish Milestone
Links: 1 preceeds 2, 3 precceds 4, 2 and 4 preceed 5.

Enjoy!
And pay attention to Total Slacks. They are not feasible, they are wrong. If resources are limited Total Slack field shall be ignored.
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Thu, 2004-12-09 15:11
#3
Vladimir Liberzon
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Alexandre,
I did not find Finish milestone field in the Project List (in PS8). Though it does not matter. A schedule should not depend on turning this option to Yes or No. I think that you agree with me. The problem is worse when the schedule is large - it is hard to discover a problem.
I don’t understand why in CC mode project schedule does not change when I change activity durations (make it 10 times less and you will see huge vast periods between task execution periods).
Do you want an example for MS Project?
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Wed, 2004-12-08 08:28
#4
Vladimir Liberzon
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Project Test consists of three activities (1, 2 and 3) and uses two resource units (a and b) available 8 hours per day. Activity 1 has 20 days duration and uses resource a, activity 2 has the same duration 20 days and uses resource b, activity 3 lasts 19 days and uses resource a. Activity 1 preceds activity 2 (FS). That’s all. Use this example in the Critical Path mode. When I tried Critical Chain mode in PS8 a schedule did not follow changes in activity durations, all activities became ALAP and so on. It worked quite strange. I remember that PSNext does not include Critical Chain. Am I right? Please inform me about the results of your testing. Best Regards, Vladimir
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Tue, 2004-12-07 14:08
#5
Vladimir Liberzon
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Yes, I did. The problem is in resource leveling algorithms. The software produces poor resource-constrained schedules and thus wrong critical chain. Do you want some example?
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Mon, 2004-12-06 18:06
#6
Vladimir Liberzon
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Alexandre,
do you know that leveling algorithms that are used in Sciforma (and Scitor) produce funny results? I like your product except its resource constrained scheduling capabilities.
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Thu, 2004-12-02 17:05
#7
Gerry Morgan
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I know what you mean, hopefully they read forums like this and make the required changes.
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Thu, 2004-12-02 12:26
#8
Vladimir Liberzon
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OK, let’s hope that some day Microsoft will be able to calculate Resource Critical Path. Do you have time to wait for this some day?
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Thu, 2004-12-02 11:46
#9
Gerry Morgan
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Hi Vladimir

Thanks for responding and verifying, it would seem that this should be a feature of MSP hopefully in a future release.

Regards Gerry
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Thu, 2004-12-02 09:55
#10
Vladimir Liberzon
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I am afraid that you have no other solution except exporting your project to Spider Project software and rescheduling it there. Other packages do not calculate resource constrained floats and thus will not show which activities are really critical.
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