I agree with you, there is an error, perhaps By Design making it a Monumental Error. There is no excuse for not to roll up corectly the dates no matter what logic is used, can be if using links or if using date constraints. A 1950's scheduler would roll up the dates by hand and would get the correct results!
Some call it a Bug, ... quite a BIG BUG.
Member for
21 years 8 months
Member for21 years8 months
Submitted by Rafael Davila on Thu, 2018-09-20 23:18
For your convenience here is query_2 image I saved before disappearing as I had the suspicion it will soon disappear. I posted the image using external image hosting service.
"I still dont see a reason of the summary task being shown as a critical sumary task." -
Repeating myself: The summary task is shown as critical because its TS=0 (and your schedule options say "Critical" ~ TS<=0). Because the underlying calculations are not based on valid network logic, Total Slack and the critical flag of summary tasks in MSP are meaningless and should be ignored.
"There is some error in the calculation of Late start of the summary task." -
As noted in the article I linked earlier, if the early start of a summary task is controlled by a subtask that is manually scheduled, then MSP over-writes the late start of the summary with the early start of the manually-scheduled subtask. I don't know why - you can call it an error if you like, though "correcting" the error would still not make the summary values meaningful. Regardless, manually-scheduled tasks are 100% incompatible with logic-driven schedules. They corrupt the float/slack calculations of all related activities, and their mere existence in your schedule is an error.
For Summary tasks in MSP - Start Slack, Finish Slack, Total Slack, and the Critical flag are meaningless and should be ignored. They are computed from the Summary's early and late dates, which typically role up from different sub-tasks without regard to logic. The particular example you've described (without reference to the invisible image) - with zero start slack and positive finish slack on an unstarted summary task - might be explained by a manually-scheduled subtask. I wrote an article on the subject a few years ago: https://wp.me/p6CCB4-4A
Member for
21 years 8 months
Member for21 years8 months
Submitted by Rafael Davila on Tue, 2018-09-18 14:04
Member for
9 years 5 monthsThanks for the detailed
Thanks for the detailed explanation Tom.
Appreciate it.
Member for
9 years 5 monthsHaha. Could be.
Haha.
Could be.
Member for
21 years 8 monthsSaurabh Lele,I agree with
Saurabh Lele,
I agree with you, there is an error, perhaps By Design making it a Monumental Error. There is no excuse for not to roll up corectly the dates no matter what logic is used, can be if using links or if using date constraints. A 1950's scheduler would roll up the dates by hand and would get the correct results!
Some call it a Bug, ... quite a BIG BUG.
Member for
21 years 8 monthsFor your convenience here is
For your convenience here is query_2 image I saved before disappearing as I had the suspicion it will soon disappear. I posted the image using external image hosting service.
Member for
18 years 11 monthsSaurabh Lele, thanks for the
Saurabh Lele, thanks for the graphics.
"I still dont see a reason of the summary task being shown as a critical sumary task." -
Repeating myself: The summary task is shown as critical because its TS=0 (and your schedule options say "Critical" ~ TS<=0). Because the underlying calculations are not based on valid network logic, Total Slack and the critical flag of summary tasks in MSP are meaningless and should be ignored.
"There is some error in the calculation of Late start of the summary task." -
As noted in the article I linked earlier, if the early start of a summary task is controlled by a subtask that is manually scheduled, then MSP over-writes the late start of the summary with the early start of the manually-scheduled subtask. I don't know why - you can call it an error if you like, though "correcting" the error would still not make the summary values meaningful. Regardless, manually-scheduled tasks are 100% incompatible with logic-driven schedules. They corrupt the float/slack calculations of all related activities, and their mere existence in your schedule is an error.
Member for
9 years 5 monthsThanks for the article and
Thanks for the article and your input Tom.
Yes, as you predicted the first sub task of "Preparation of PR" is manually scheduled.
But, unlike the summary task, both the sub-tasks have non-zero start and finish slacks.
I still dont see a reason of the summary task being shown as a critical sumary task.
Al
[[wysiwyg_imageupload:6097:]]
so attaching the snap with Early and late Starts and finishes based on the calculations shown in your article.
There is some error in the calculation of Late start of the summary task. (Check attached image)
Member for
9 years 5 monthsAttaching the jpeg image.
Attaching the jpeg image.
[[wysiwyg_imageupload:6096:]]
Member for
18 years 11 monthsSaurabh Lele,For Summary
Saurabh Lele,
For Summary tasks in MSP - Start Slack, Finish Slack, Total Slack, and the Critical flag are meaningless and should be ignored. They are computed from the Summary's early and late dates, which typically role up from different sub-tasks without regard to logic. The particular example you've described (without reference to the invisible image) - with zero start slack and positive finish slack on an unstarted summary task - might be explained by a manually-scheduled subtask. I wrote an article on the subject a few years ago: https://wp.me/p6CCB4-4A
Member for
21 years 8 monthsThe image is not visible.
The image is not visible.