Hi Rafael,

If the constrains is used as fixed milestone not tied by logic to any schedule activity. I’m with you "It’s really a BAD practice". otherwise what’s the use of Baseline?

Thanks

Hi Rafael,
I respect your opinion because everyone has own belief of what is wrong and what is right. I don’t see any wrong on the authors preference of using milestone for constrain date. Noted: “This is not mandatory” Inserting a milestone at the end or beginning of a task and use as constrain is not actually a bad idea. It’s easier to find because the scheduler knows that constrain are only on milestones instead on multiple number of task. Technically it’s correct because we cannot constrain start and finish of a task at the same time while milestone has only one date (either start or finish).
“The only legitimate use of a constrain is to mirror an impost on the schedule”
It doesn’t specify whether it should be a task or a milestone.

“Constrained dates impact the calculation of ‘Float’.” I agree!

“The only way negative float can be generated in a schedule is by the presence of a fixed date of some form” If no baseline to measure how can it generate a negative float if no fixed end? How can you justify it’s a delay if no basis?

“A total float value less than zero indicate that the activity late finish date is scheduled prior to the activity early finish date and the calculated critical path is not feasible.”
“I believe this is a wrong functionality adopted by Primavera Products, that is wrong and that is accepted because of some PMI members having interest on Primavera/Oracle support of the PMI.”
Hehehe… no comment
here is a good one Float is it real?

Rodel,

About your reference, which I like, I have the issue on the author not being clear about his preference on the issue on date-constraints. They are wrong and their use should be considered bad practice.

Footnote: "A personal preference of the author of this paper is to place all date constraints on Milestones. This is not mandated [come on be brave, is wrong], but it makes finding and managing constrained dates as the project progresses much easier. The practice also makes the identification of ‘errors’ easier – imposed dated on normal tasks are obviously in the wrong place. Constrained dates impact the calculation of ‘Float’. The only way negative float can be generated in a schedule is by the presence of a fixed date of some form [come on be brave, negative float is wrong]."

The same goes with the PMI Practice Standard for Scheduling that allows for The “Finish Not Earlier Than” constraint to be used sparingly. Also in the same document the PMI accepts Negative Float, a computation that overrides CPM backward computations. They say “A total float value less than zero indicate that the activity late finish date is scheduled prior to the activity early finish date and the calculated critical path is not feasible.” I believe this is a wrong functionality adopted by Primavera Products, that is wrong and that is accepted because of some PMI members having interest on Primavera/Oracle support of the PMI.

Best regards,
Rafael

Hi Jukka,

For me, it’s not a measure of minimum or maximum.

It is the comprehensiveness of your schedule which shall represent the realistic tasks and methods on how you are going to build your project.

I may suggest that you don’t listen to Samer and Mike (maybe sometimes), as for example: your project is to install lighting posts (and nothing else, wirings, others not included in the scope). With this, you can work on each post independently and without any relationship with other posts.

Best regards

Hi,

Keep the Start and Finish Activities with open ends only.

With kind regards,

Samer

Dear Jukka,

The best thing that you can do is pick up a basic book and read the basics of scheduling. Using the tool will not make you a good carpenter.

Start out with a simple example from the scheduling book that you have and implement it in the software. Then you start adding more details to your program of works.

You should be able to answer the 4 points within 1 minute or less after reading the book.

With kind regards,

Samer