% Complete Calculation

[SwapnaK]

Trying to understand how the Task % Complete given at the parent task
gets distributed to subtasks under it. Is it based on duration, work,
dates or anything else? Please hlep...!!!

 

[salgud]

Trying to understand how the Task % Complete given at the parent task
gets distributed to subtasks under it. Is it based on duration, work,
dates or anything else? Please hlep...!!!

Actually, it doesn't. It's the other way around. The % completes of the
subtasks determine the % complete of the summary line, based on actual
hours worked over total hours for all subtasks.
Keep in mind, % Complete is a very poor way to input task progress. Actual
hrs worked and remaining hrs give much better results.
Hope that helps in your world.

 

[SwapnaK]

Thank You.

But in Microsoft Project it allows me to enter % Complete at th
summary task level and then it distributes the % Complete to it'
subtasks. For eg...if I have a Summary Task of Skill Management and
have subtasks under it as follows:


- Skill Management

- Add
- Edit
- View
- Delete
- Search

For me it makes sense to list out all the subtasks so the develope
knows what is needed to be done. But when it comes to submitting th
status the developer may want to report % Complete at the Summary Tas
level. MPP allows that and then it distributes the status to it'
subtasks. However I am not understanding the way it's distributing. I
there any algorithm or method? Any help in this regard is greatl
appreciated

 

[Rod Gill]

I agree with Trevor, using % complete to track progress is a very low
accuracy method. If a task with 10h of work is 50% complete did it start on
time? did it take 5h to do 50% or 8? is there 5h to go or 8? Actual start,
and actual work and remaining work or actual Duration and remaining duration
are much better. Recording actual hours each day is better again.

--

Rod Gill
Microsoft MVP for Project

Author of the only book on Project VBA, see:
http://www.projectvbabook.com

 

[Steve House]

% Complete only deals with durations, by definition. It is strictly a
measure of the passage of time and is not an indication of the amount of
work performed or progress on the deliverable to be produced. As others
have pointed out, the summary % complete is normally computed upwards from
posted actual durations of the subtasks, not the other way around. You can
measure the number of days work has taken place on an observable activity
versus the number of days the work is expected to last but you can't
estimate the % Complete on a summary task because it literally does not
exist as an observable, measurable activity. It is a composite of a number
of different activities grouped together for reporting purposes, nothing
more. The summary percent complete is calculated by taking the total of the
actual durations worked on all of the subtasks and dividing that sum by
total durations of all the subtasks. The resulting percentage, in turn, is
multiplied by the duration of the summary task to compute an effective
actual duration of the summary. This actual duration is subtracted from the
summary total duration to come up with a summary remaining duration. That
remaining duration is subtracted from the summary end date to provide a
final effective "worked through" date for the summary task.

In P2007, when you enter a % Complete directly for a summary task it
reverses that logic. Takes your input % Complete, subtracts it from 100 to
calculate the % Remaining, subtracts that from the finish date to result in
an effective worked through date. It then uses that date to set a
completed-through date for each of the subtasks. If they're scheduled to
finish before that date, they're 100% complete. If they're in-progress on
that date, they're whatever percent complete that date represents. If
they're not yet scheduled to start, they're 0% Complete.

Hope this helps

 

[SwapnaK]

Hi Steve, Thank you. That was helpful.

TASK 6 DAYS WED 5/7/08 WED 5/14/08 50%
*1 6 days Wed 5/7/08 Wed 5/14/08 45%*
1.1 2 days Wed 5/7/08 Thu 5/8/08 100%
1.2 3 days Thu 5/8/08 Mon 5/12/08 47%
1.3 4 days Fri 5/9/08 Wed 5/14/08 10%
1.4 5 days Thu 5/8/08 Wed 5/14/08 28%
1.5 3 days Wed 5/7/08 Fri 5/9/08 81%
*2 5 days Wed 5/7/08 Tue 5/13/08 60%*
2.1 3 days Wed 5/7/08 Fri 5/9/08 81%
2.2 5 days Wed 5/7/08 Tue 5/13/08 48%

Above one is my project data. I have reported 50% at the Summary task
level. Here is my understanding from your explanation.

Project is 50% complete. Duration is 6 days. So I will take remaining
50% progress and calculate the completed-through date, which is
5/9/2008. So all tasks that end before that will have 100% status. That
explains me the status of the first subtask i.e., 1.1. However not sure
about the calculation of the remaining tasks. Can you please shed some
light on the point 'If they're in-progress on that date, they're
whatever percent complete that date represents.'

Thank you in advance.

 

[Steve House [MVP]]

We have a task that began Monday at 8am and is expected to take 5 days to
finish Friday at 5pm. It is now Wednesday at 5pm and we have worked as
planned and it appears that we really will finish on-schedule. By
definition the task is 60% complete. But if it's Wed at 5pm and it looks
like we won't really finish until Monday at 5, the task is only 50% complete
(3 days past out of now 6 days required to finish).

 

[SwapnaK]

Steve,

Somehow I am confused. Would you mind explaining the % Calculation of
the Task 1.2 please?

 

[Steve House [MVP]]

I'll give it a shot but first what are the links between the tasks?

 

[SwapnaK]

Hi Steve,

No links as of now between tasks. BTW, does linking change Statu
Calculation as well? If yes, probably once i am clear on this, I migh
request again for explaining that scenario as well. .

 

[SwapnaK]

Hi Trevor,

How did we arrive at .42 d calculation for each task? I think if I ca
understand that my doubt will be cleared.

Thanx in advance.

 

[SwapnaK]

Hi Steve,

Please Help!!!

 

[Steve House]

You're correct, it doesn't really matter what the links are AFAIK. SNET
constraints on some of the tasks would have the same effect. Just wanted to
setup the same exact starting plan Swap had.

 

[Steve House]

Haven't had much time the last few days - I'll get back to ya!

 

[Steve House]

Finally found some time to look at this.

Linking won't change status calcs as such but it will effect the start and
end times of tasks and that might. I'm thinking about how task 1.2 got to
be starting on May 8th and 1.3 got to May 9th. If it's a SNET constraint it
will probably start at 8am. But if it got there some other way, it might
start late in the day. It becomes important because we need to be able to
figure out how many "actual duration minutes" are being generated for each
minute worked. Remember, Project does ALL of its duration calculations in
minutes to the nearest 10th. Because not all of the tasks are going on all
of the time, the 50% complete point for the whole project does not
correspond to excatly 3 days into the project, or Friday at 5pm. Instead,
the 50% mark is on Friday roughly about 11 am. There are a total of 12000
minutes of duration to be worked [(2+3+4+5+3+3+5) * 8 * 60] and 50% complete
on the summary means we've worked 6000 of them. To get the percentages for
all the tasks and summaries, we have to go minute-by-minute from Wed at 8am
until Fri at 11+am and calculate the number of Actual Duration minutes each
clock minute represents. For instance, on Wed we have tasks 1.1, 1.5, 2.1,
and 2.2 taking place - each clock minute passing earns us 4 AD (Actual
Duration) minutes. On Thurs we have 1.1, 1.2, 1.4, 1.5, 2.1, and 2.2 taking
place - each clock minute earns us 6 AD minutes. On Fri we have 1.2, 1.3,
1.4, 1.5, 2.1, and 2.2 to also earn 6 AD minutes for each passing clock
minute.
Look at some status dates

Wed 5pm: Cummulative AD minutes worked 4*8*60 = 1920
Thur 5pm: Cummulative AD minutes worked 6*8*60+1920 = 4800
Fri 11am: Cummulative AD minutes worked 6*3*60+4800 = 5880

so the 6000 total minutes worked milestone occurs a few minutes after 11am
on Fri, roughly 11:05am. There are some slight discrpancies due to
accumulating roundoff errors. To figure the percent complete of each of the
individual subtasks, count up the number of minutes spent of each task
between its start and 11:05 am Friday and divide by the total duration of
the task in minutes. For task number 1.2, for example, its duration is 3
days or 1440 minutes. It starts Thur 8am so by Friday at 11:05, 665 minutes
have been worked on it. (655/1440)*100 = 46.2%, close enough to the
displayed value of 47% for government work <grin>.
--
Steve House [Project MVP]
MS Project Trainer & Consultant
Visit http://project.mvps.org/faqs.htm for the FAQs