Ingeneer said:
This goes back to my original question where I stated that I would expect
the
summary duration to show 5 days but it shows 5.56 days, not the 5 days
that
you indicated it should.
So the 5 day duration that I thought should result actually does,
according
to your explanation, but Project shows it as something different.
That was the reason for my posting.
Ingeneer,
OK, somewhere during our discussion misunderstanding led to confusion,
and I think I see where the discussion went astray. During our
discussions we talked about two fields - Duration and Actual Duration.
In an earlier post you said you expected the actual duration to be 5
days not the 5.56 that was shown for the summary line. I asked why you
would expect that [actual duration] to be 5 days. You responded back
that you expected the duration (not actual duration) to be 5 days
because that is what actually elapsed. Then you went on to say that the
summary line duration equals the amount of days elapsed once each task
reaches 100%. In other words you didn't quite answer the question -
instead you switched fields. Unfortunately I didn't pick up on the
switch there but nonetheless everything I have said is still correct.
OK, so where does that leave us. For your original example, the summary
line Duration field is 15 days and the summary line Actual Duration
field is 5.56 days. You have already correctly figured out the formula
Project uses when it calculated summary line actual duration.
Does that clarify things?
John
Project MVP
:
What's the definition of working time? If an 8 hour day starts at 8
am
and
ends at 5 PM, a task starting on Monday at 8am and ending on Friday
at
5pm
has 5 days of working time? If the summary task depicts the working
time
of
the tasks below it, then if the first task starts on Monday at 8am
and
the
last task ends on Friday at 5pm isn't that 5 working days?
Ingeneer,
First, working time is defined under Tools/Change Working Time.
Second, yes, the task starting on Monday and finishing on Friday has 5
days of working time, given the standard calendar.
Third, a summary line is not a task even though it is unfortunately
called that in many places. If the first task under a summary line
starts on Monday at 8:00 am and the last task under that summary line
finishes at 5:00 pm on Friday, then yes, the summary line will show 5
[working] days in its Duration field. This is analogous to the example
I
gave in my previous response.
By the way, all of the above also assumes that the definition of a
working day from a duration standpoint is still set at the default 8
hours per Tools/Options/Calendar tab.
Mind telling us where all this is going?
John
Project MVP
:
I expected the summary duration to equal five days because that's
what
actually elapsed. If you track the schedule through to close,
the
summary
duration eventually equals the amount of days elapsed once each
task
reaches
100%.
Ingeneer,
The summary line duration only equals the sum of the subtask
durations
IF all subtasks are linked finish-to-start with no lead or lag.
Let's
take this alternate scenario. I have 3 tasks of 5 days duration
each.
They all start on the same day. The summary line for those tasks
will
therefore also be 5 days. If all three tasks are 100% does that
mean
the
total duration was 15 days? No, it is still just 5 days.
It all comes down to the definition of duration. In Project
duration is
the working time between the start of a task and the finish of that
task. For a summary line it is the working time from the start of
the
earliest subtask to the finish of the latest subtask.
Now, you may be confusing duration with work. Duration is time
span,
work is effort. If the same three tasks above each required 40
hours of
work then the total work expended is indeed additive and equals 120
hours.
Hopefully this clarifies it.
John
Project MVP
:
Have a project with one summary task and six tasks. Tasks A,
B
and C
are
each 5 days duration. Tasks D, E and F are each 4 days. A
is
linked
to
B is
linked to C in FS relationship. D is linked to E is linked
to F
in
FS
relationship. This results in two paths. Duration for the
summary
task
then
is shown as 15 days. Project is set to start on Monday
morning
at 8
am.
During tracking of progress after the first week, Task A
takes 5
days
and
is
100% complete. Task D takes 4 days and is also 100%
complete.
Task
E
starts
upon completion of task D, takes 1 day duration and is 25%
complete.
Project
calculates the ACTUAL duration of the summary task as 5.56
days
instead
of
what would be expected 5 days. The question is why? It
appears
to
calculate
the percent complete by dividing the sum of the individual
actual
task
durations by the sum of the individual durations. In this
case
that
would be
10 (5+4+1) divided by 27 (5+5+5+4+4+4) equals 37%. It then
multiplies
the %
complete by the duration to get the actual duration to get
5.56
(.37*15).
This doesn't seem correct. Why wouldn't it be 5 days? What
am I
missing?
Ingeneer,
Why would you expect the actual duration of the summary line to
be
5
days? First, you have to realize that the summary line is NOT a
task,
it
is simply a summary of the subtasks under it.
You have figured out the correct formula used by Project for
calculating
actual duration and % complete for a summary line and it is as
you
can
see, a weighted value of the subtasks. The formula is correct
and
it
does make sense since it is taking into account the overall
summary
of
the actual performance tasks (i.e. subtasks).
Hope this helps.
John
Project MVP
