MSP - summary task field calculation

[YLE]

I think I understand how duration field calculated at the task level. My
confusion is the summary task level: %Comp, Dur, A.Dur are recalculated when
I change one or another parameter at the task level, but the results don’t
make too much sense to me, see below the example. How did I get 18% comp and
1.27 Actual Duration ??? at ST level. Also 5.73 Remaining duration. This is
just an example.

%Comp Dur A.Dur R.Dur
ST 18% 7d 1.27d 5.73d
t1 14% 7d 1d 6d
t2 25% 4d 1d 3d

Thanks,

Yakov

 

[John]

I think I understand how duration field calculated at the task level. My
confusion is the summary task level: %Comp, Dur, A.Dur are recalculated when
I change one or another parameter at the task level, but the results don’t
make too much sense to me, see below the example. How did I get 18% comp and
1.27 Actual Duration ??? at ST level. Also 5.73 Remaining duration. This is
just an example.

%Comp Dur A.Dur R.Dur
ST 18% 7d 1.27d 5.73d
t1 14% 7d 1d 6d
t2 25% 4d 1d 3d

Thanks,

Yakov

Yakov,
This question has been asked many times before but mostly in the main
newsgroup, microsoft.public.project. This newsgroup (the one you posted
in) is primarily for questions relating to Project developer issues.

Nonetheless, this was one of my responses to a similar question posted
previously.
Project calculates summary line progress based on the following formula:
summary line progress = (sum of Actual Durations of subtasks)/(sum of
Duration of subtasks) x 100%

John
Project MVP

 

[YLE]

Thanks, John.
and then the ST actual duration is recalculated based on ST%Comp and same to
Remaining duration for summary. Is this correct?
Then I have tough task to explain to people the meaning of calculated values
- remaining Duration in the example for the ST is 5.73 days, though in
reality it looks like 6d - the bigger number out of two remaining durations
(t1 and t2).
Thanks again and apologize for posting in th wrong section

 

[John]

Thanks, John.
and then the ST actual duration is recalculated based on ST%Comp and same to
Remaining duration for summary. Is this correct?
Then I have tough task to explain to people the meaning of calculated values
- remaining Duration in the example for the ST is 5.73 days, though in
reality it looks like 6d - the bigger number out of two remaining durations
(t1 and t2).
Thanks again and apologize for posting in th wrong section

Yakov,
You don't need to apologize for posting in the wrong newsgroup. It's
just that if you post in the most appropriate newsgroup, you are more
likely to get the best answer.

When it comes to summary tasks you have to remember one thing. A summary
line is not a task at all, rather, it is a summary of the subtasks below
it. There are probably several ways to summarize certain types of data
(particularly timespans and progress) for a summary line. For example,
does a weighted average best define progress or is some other method
more appropriate. In the case of Project, the developers decided that a
weighted value of the subtasks made the most sense. Hence the formula I
described previously. Remaining Duration at a summary level is simply
the Summary Duration minus the Summary Actual Duration, the former being
the working time from the start of the earliest subtask to the finish of
the latest subtask, and the later being calculated by the formula.

As far as explaining this to someone it shouldn't be a problem. Project
is designed around time scheduling algorithms and user defined or
formula based data. That's simply the way it works. Customizable fields
are available to meet a particular users needs, but the basic scheduling
and cost fields are based on common accepted project management
techniques.

John
Project MVP