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Link remaining duration and schedule %complete

6 replies [Last post]
Wed, 2005-03-02 09:41
kamran hazini
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Joined: 10 Jan 2005
Posts: 38
Groups: Petro-Chem / Oil & Gas
Dear Planners,
I was searching through the previous threads about the advantages and disadvantages of relationship between remaining duration and percent complete (autocost rules) in our plans and when it is better to use this feature. I noticed there was not any thread focusing on this subject.
As far as I understand, this check box is on by default. But sometimes it is misleading because the period of remaining work is not exactly related to the physical progress percent. In addition, by cutting this relation, you have to gather remaining duration as well as progress% from supervisors.

I would appreciate if you, planners, tell me your valuable experiences for using both alternatives in your time schedules and what was the main issues. In order to have an efficient discussion, I suggest to mention also the type of project you dealt with. (E,P,C)

cheers
kamran
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Replies

Thu, 2005-03-10 03:10
#1
kamran hazini
User offline. Last seen 11 years 33 weeks ago. Offline
Joined: 10 Jan 2005
Posts: 38
Groups: Petro-Chem / Oil & Gas
I have experienced that not many of our activities are linear. Maybe it is useful for management tasks or something called level of effort. They are progressing in a linear manner as long as project proceeds. I don’t know many engineering or construction activities achieving progress linear and according to their duration. So why this is P3’s recommendation that set this as default and uses in his sample projects?
Maybe one solution was to assign a resource curve for driving resources to calculate the progress/remaining duration based on the distribution you defined.(Normal, Back loaded, etc) However, you are not allowed to allocate curve for driven resources. I don’t know why?!
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Tue, 2005-03-08 22:29
#2
Hermie LaO
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Hi Guys, as a rule the first thing I always do is remove the link between schedule percent complete and remaining duration. For several reasons:
1. During the planning stage activity durations are based on best estimates of productivity of the resources which in all likelihood will change once the project is underway;

2. Linking the two assumes linear progress of an activity ie 10 day activity, 50% complete does not necessarily mean 5 days to go to complete the task.

3. There are often tasks with are performed faster than planned and then linger at the end. ie 10 day activity. 80% complete in just under 3 days and the activity hangs another 20 days to do the remaining 20%. This is true specially for resource driven activities.

Hope this helps
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Tue, 2005-03-08 15:03
#3
kamran hazini
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Posts: 38
Groups: Petro-Chem / Oil & Gas
agree. But besides of that we have a progress curve showing actual% vs. planned that we should be careful about for both undergraduate and graduate people!
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Sat, 2005-03-05 01:17
#4
Ronald Winter
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Unless you are being paid by cost and percent complete, and unless these durations are longer than 20 days; then what does it matter?

We are measuring the estimated completion deate. We do this by estimating remaining duration for each activivity. The rest is a mental practice intended to keep undergratuates busy and out of trouble!

Just estinate remaining duration as well as you can and modify the logic to indicate your current work plan. If you do this, then consider yourself above the other 95% of the other Schedulers out there and take your wife out to dinner and play with the kids. You deserve the time off.

Good luck!
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Sat, 2005-03-05 00:19
#5
kamran hazini
User offline. Last seen 11 years 33 weeks ago. Offline
Joined: 10 Jan 2005
Posts: 38
Groups: Petro-Chem / Oil & Gas
Dear Ronald, thanks for your advice. Anyhow, assume you have a defined procedure for getting progress by using some steps (such as study, design, drafting, checking, issue of drawings) with a certain actual progress for each step. Having this link on, P3 will calculate remaining duration for me that is directly based on the original duration and my actual progress. What if this rule is not applicable for remaining work?
For example, duration from study until checking is 8 days and checking to issue is 2 days but I have left 40% of my physical progress for just issue of the document due to the importance.
So, after day 8 with 60% progress P3 will show me RD equal to 4 days while it is only 2 days in real world. Then I have to put an Expected Finish for it which then increases my progress from 60% to 80%!
Maybe this example is also valid for construction phase; you are making progress out of piping erection for each line but you have reserved a substantial value for inspection/release that also can be done much faster.
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Wed, 2005-03-02 11:20
#6
Ronald Winter
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In construction, there is a definite reason for de-linking percent complete and remaining duration. P3 treats them differently. Activity percent complete is used to drive the cost calculations. Remaining Duration is used to drive the CPM calculations.

Having said that, I normally recommend that you keep the two linked unless the reporter is committed to the extra work. In my experience, it is difficult enough to get consistent, accurate remaining duration estimates. Asking for an additional accurate cost percent complete is usually beyond expectation. Good luck!
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