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Resource Curves

5 replies [Last post]
Fri, 2004-10-22 09:14
Erik Jonker
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I find P3 the earned value calculation of resource curves aren’t applicable to any real scheduling activities.

They can not be used for any activities where the actual duration can be longer or shorter than the original duration.

Can they be in used in any detailed schedule? Because if everything went perfectly as per schedule, why need schedulers?

Like to see what everybody thinks.
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Replies

Sat, 2004-10-30 01:17
#1
Erik Jonker
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Hi Alex,

In the previous calculation, (Percent of duration) equals (Actual Duration) divided by (Actual + Remaining Duration).

It does not help if you change any settings in the autocost rules.

For more info see P3 knowledge base ID : 200181143955

Regards,

Erik
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Fri, 2004-10-29 10:36
#2
Erik Jonker
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Hi Alex,

My problem is actually the calculation of earned value when using a resource curve (Linear, triangular etc.) on a specific activity.

The way it calculates the earned value when a resource curve is allocated to an activity, is as follows:

Actual Duration = Data Date - Actual Start

Actual Duration
Percent of duration = ---------------------------
Actual + Remaining Duration


Resource Percentage = Percent of duration applied to curve.

On the curve: X-axis = Percent of duration
Y-axis = Resource Percentage

On a linear curve: Percent of duration = Resource Percentage

The problem is the following:

If an activity gets delayed, the actual duration increases, but the remaining duration remains the same.

The longer an activity gets delayed the remaining duration will become more insignificant.

Your percent of duration will become closer to 100% as time marches on.

This will be compounded by a curve tapering off at the end.

It has happened to a collegue of mine who used resource curves to get a better resource loading on activities. We were over progressing by 2%. Luckily we did not have many delayed activities and were still on schedule after we fixed the problem.

I would not want to see what would happen if a project is behind schedule and you have to fix this.

I see planners using using resource curves to "fix" planning issues.

IT IS DANGEROUS!!!!!!!


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Mon, 2004-10-25 02:15
#3
Alex Wong
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Erik

I dont really understand your problem. However, I will have a guess that your possibly need to look at your cost & Resource setting (Accounting Rules). I dont have a problem when using EVM in P3, on both activity and resource level. I can accurately plot the EV curve according to the actual resource loading. Please check your Setting especially in the
Remaining Cost = Budgeted Cost -/+ Actual Cost

The only point I find P3 is not very good is the report printing do not have EV in their resource curve. It is only printable in Layout View. Other than EV is running ok.

In addition, if you have a target programme (Baseline) You need to also be careful with BQ/BC and CAC/QAC. They need to match.

IMHO, the software is only a tool, and we are the Driver.

Enjoy planning and hopefully this time around it works for you.

Alex
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Mon, 2004-10-25 01:40
#4
Erik Jonker
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Thanks Jaco

I’ve actually got a problem with the calculation. It does not use the resource % complete. It uses Remaining Duration over Actual Duration (Data date - Actual Start).

If an activity with a resource curve is 20% complete and delayed for a long time, it can show an earned value up to 90% (depends on OD).

Thus, the longer you delay the activity, the more it progresses.

It does not make sense to me. It is also very dangerous if you us it and don’t know exactly how it works.

Regards,

Erik
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Sat, 2004-10-23 08:06
#5
Jaco Stadler
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Hi Eric

Please confirm when you do a progress update do you update at the resource level or at activity level. Are you using Remaining Duration or % Complete.

I have found if I apply % complete at resource level I dont have a problem with earned Value. If you use it at Activity level you seem to have a problem but it does make sence since Earned Value is based on Resources not activity’s planned.

I hope this assist

Cheers






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