G
Guest
Can someone give me a definition of how the Actual
Duration on a Summary Task line is calculated? Thanks
Duration on a Summary Task line is calculated? Thanks
J
John
This was my response to a similar post on 15 April of this year.
Duration for summary tasks is simply the number of working days between
the subtask under it with the earliest Start date and the subtask with
the latest Finish date. This is also true of the Project Summary Task.
However, it sounds like you are actually looking at the Actual Duration
field. For a summary task this value is calculated as the ratio of the
sum of subtask Actual Durations to the subtask total Durations times the
Duration of the summary task. For example, assume a summary task with a
total Duration of 62 days has three subtasks. The first has 62 days
duration and is 100% complete. The second has 20 days and is 100%
complete. The third has 20 days and is 50% complete. The sum of Actual
Durations for the 3 subtasks is:
100% * 62 + 100% * 20 + 50% * 20 = 92 days
The total Duration of all three subtasks is 102 days. The ratio is
therefore 92/102 = 90.1%. Multiplying this by the total Duration of the
summary gives and Actual Duration for the summary task as:
90.1% * 62 = 55.92 days.
Hope this clarifies things.
John
Duration for summary tasks is simply the number of working days between
the subtask under it with the earliest Start date and the subtask with
the latest Finish date. This is also true of the Project Summary Task.
However, it sounds like you are actually looking at the Actual Duration
field. For a summary task this value is calculated as the ratio of the
sum of subtask Actual Durations to the subtask total Durations times the
Duration of the summary task. For example, assume a summary task with a
total Duration of 62 days has three subtasks. The first has 62 days
duration and is 100% complete. The second has 20 days and is 100%
complete. The third has 20 days and is 50% complete. The sum of Actual
Durations for the 3 subtasks is:
100% * 62 + 100% * 20 + 50% * 20 = 92 days
The total Duration of all three subtasks is 102 days. The ratio is
therefore 92/102 = 90.1%. Multiplying this by the total Duration of the
summary gives and Actual Duration for the summary task as:
90.1% * 62 = 55.92 days.
Hope this clarifies things.
John
G
Guest
I came across your answer just about an hour ago, and I
applied the theory to my project. However, it didn't come
out the same. Here is the example from my project.
My summary duration is 1606 days
Proj. A is 55 days @ 100%
Proj. B is 1 day @ 0%
Proj. C is 585 days @ 0%
Proj. D is 290 days @ 0%
100%*55+0%*1+0%*585+0%*290 = 55 days
Total duration of all four subtasks is 931 days
55/931 = 5.91%
5.91% * 1606 = 94.91 days
My schedule shows that actual duration for the summary
task as 53.5 days.
HELP>>>>
applied the theory to my project. However, it didn't come
out the same. Here is the example from my project.
My summary duration is 1606 days
Proj. A is 55 days @ 100%
Proj. B is 1 day @ 0%
Proj. C is 585 days @ 0%
Proj. D is 290 days @ 0%
100%*55+0%*1+0%*585+0%*290 = 55 days
Total duration of all four subtasks is 931 days
55/931 = 5.91%
5.91% * 1606 = 94.91 days
My schedule shows that actual duration for the summary
task as 53.5 days.
HELP>>>>
J
JackD
I think that your calculation (and perhaps project's) is off because of the
presence of gaps in the summary task.
Also, how long is the 55 day task? Depending on how things get
rounded/summarized it may actually be a bit shorter.
If I had this problem and wanted to get to the bottom of it I'd simply start
with one subtask and then add another and determine how it changes.
-Jack
presence of gaps in the summary task.
Also, how long is the 55 day task? Depending on how things get
rounded/summarized it may actually be a bit shorter.
If I had this problem and wanted to get to the bottom of it I'd simply start
with one subtask and then add another and determine how it changes.
-Jack
J
John
Are you sure calculation is set to automatic? Even if there are gaps
between subtasks (i.e. delay between two subtasks), the formula I posted
is still valid. If calculation is not automatic, you will see Actual
Duration on an individual task change when % Complete is changed but the
Actual Duration for the summary line will remain at its previous value.
If calculation is set to automatic and you are still getting the strange
result, give us a little more information on exactly how the subtasks
are structured under the summary or you can send me a zipped file and I
will figure it out.
John
between subtasks (i.e. delay between two subtasks), the formula I posted
is still valid. If calculation is not automatic, you will see Actual
Duration on an individual task change when % Complete is changed but the
Actual Duration for the summary line will remain at its previous value.
If calculation is set to automatic and you are still getting the strange
result, give us a little more information on exactly how the subtasks
are structured under the summary or you can send me a zipped file and I
will figure it out.
John
A
Angela
Yes, the calculation is set to automatic, but I'm figuring
the other factor such as FF relationships and two lag
times that I have in there are what is making the
difference. I just don't know how to apply these to the
formula you gave me. The file I'm working with is VERY
large. I have over 11K task lines with hundreds of sub-
projects.....Thanks
the other factor such as FF relationships and two lag
times that I have in there are what is making the
difference. I just don't know how to apply these to the
formula you gave me. The file I'm working with is VERY
large. I have over 11K task lines with hundreds of sub-
projects.....Thanks
J
John
Angela,
It's nice to finally have a name for the poster.
You've piqued my interest as to why the information I gave you is not
working. It is possible I'm missing something and if I am, I'd like the
opportunity to figure out what it is. I have no problem looking at
whatever size file you have (as long as it is zipped) but if the issue
is demonstrated in the 5 lines (4 subtask and one summary), why not just
replicate those in a separate new file and send that to me. If the file
contains sensitive information, leave out resources and change the task
names to gerneric descriptions. Those details have nothing to do with
the problem you are experiencing.
John
It's nice to finally have a name for the poster.
You've piqued my interest as to why the information I gave you is not
working. It is possible I'm missing something and if I am, I'd like the
opportunity to figure out what it is. I have no problem looking at
whatever size file you have (as long as it is zipped) but if the issue
is demonstrated in the 5 lines (4 subtask and one summary), why not just
replicate those in a separate new file and send that to me. If the file
contains sensitive information, leave out resources and change the task
names to gerneric descriptions. Those details have nothing to do with
the problem you are experiencing.
John
J
John
People,
Angela sent me a portion of her file. After reviewing her file
structure, this is the response I gave her.
You didn't mention that the 4 "subtasks" were themselves summary lines.
That changes the way the formula must be applied. The formula I gave you
is still valid but it will have to be applied to each performance task.
For example, the total Duration for all performance tasks under each of
the second level summary lines is:
Project A 13.33
Project B 1
Project C 176.14
Project D 209.72
The sum of those is: 400.19
So, the ratio is:
13.33/400.19 = .0333091
When multiplied by the Duration at the top summary line, we get:
.0333091 x 1606 = 53.49
Wala! The answer you are looking for.
Hope this helps to clarify things.
John
Angela sent me a portion of her file. After reviewing her file
structure, this is the response I gave her.
You didn't mention that the 4 "subtasks" were themselves summary lines.
That changes the way the formula must be applied. The formula I gave you
is still valid but it will have to be applied to each performance task.
For example, the total Duration for all performance tasks under each of
the second level summary lines is:
Project A 13.33
Project B 1
Project C 176.14
Project D 209.72
The sum of those is: 400.19
So, the ratio is:
13.33/400.19 = .0333091
When multiplied by the Duration at the top summary line, we get:
.0333091 x 1606 = 53.49
Wala! The answer you are looking for.
Hope this helps to clarify things.
John
J
JackD
John,
I think it is spelled viola not Wala. (but I'm pretty sure I am missing
accent marks...)
-Jack
K
Kevin Swan
Voila!
Viola is a small violin.
Viola is a small violin.
JackD said:
J
John
Kevin,
So what's a "wala" then - perhaps a small wallaby
John
So what's a "wala" then - perhaps a small wallaby
John
S
Steve House
Actually a viola is a large violin - plays a deeper note than the violin,
more of a baritone than a soprano.
Steve
more of a baritone than a soprano.
Steve
J
JackD
We are all wrong.
At least I can claim I was typing upside down.
-Jack
At least I can claim I was typing upside down.
-Jack
M
Mike Glen
It usually plays in the Alto clef as it is more of an Alto range than a
baritone, which would be between a Cello and a Double Bass.
Mike
baritone, which would be between a Cello and a Double Bass.
Mike