Duration is displayed incorrectly with weekend work

[Norman Goldsmith]

MS Project 2002 SP-1, Windows XP

Project with two tasks, project starts on 2 February. Standard Gantt chart
displayed, entry table.

Task 1, duration 5 days, Start & End dates (copied & pasted in directly)
"February 2, 2009 8:00 AM" "February 6, 2009 5:00 PM", no calendar, sole
subtask of a summary that exactly repeats start, end and duration.

Task 2, duration 2 days (displayed), Start & End dates "February 7, 2009
8:00 AM" "February 8, 2009 5:00 PM", uses Weekend Calendar where only
Saturday and Sunday are workdays. Sole subtask of a summary that shows the
identical start and end dates but shows duration of 0 days!

Task 2 is linked FS to Task 1.

At the highest level another summary task, that has the two summary tasks as
subtasks. This task has start & end dates of "February 2, 2009 8:00 AM"
"February 8, 2009 5:00 PM". It has no assigned calendar and shows that the
duration is 5 days. Turning on the Project Summary task repeats the
information including the 5 day duration despite the span of 7 days.

On the Gantt chart side, all of the bars are of the correct length and
placement.

In the real project, tasks using the two calendars will be placed under a
single summary task. Is there a fix so that the duration field reports the
elapsed time correctly?

Thanks,

 

[Steve House [MVP]]

Summary tasks reference their durations to the Project Calendar by default.
While you're Weekends calendar has the 2-day task in question taking place
on Saturday and Sunday, as far as the calendar governing the summary task is
concerned those two days are non-working and do not count in duration, hence
0 duration for the summaryeven though the subtask is showing 2 days
duration. Durations aren't additive to the summary. If this apparent
discrepancy actually makes a difference (and I don't know why it should
since the start and finish dates are still correct) one workaround wound be
to create a calendar, called perhaps "7 Days" that shows normal work-hours
on Saturday and Sunday as you have for the rest of the week and assign it as
the task calendar for summary tasks. But there's a big drawback to this in
that it will lead now to INFLATING the durations for summary tasks that
extend over weekends - a 10-day duration task starting Monday will end the
Friday of the following week if it has the normal standard calendar. But a
summary whose is its parent will show a duration of 12 days if the summary
uses a 7-day calendar.

 

[Norman Goldsmith]

Rod,

Ok - duration measures work(ing days), not the time between events (like
start, finish) - that's a subtle point of defining terms that I missed.
However, folks reading the printout are even less likely to grasp the
notion. Can I customize a field to show that the time between start and end
is n days, where n is not necessarily an integer?

Norm

No! Duration is always in working days. So 1w by default is 40 working
hours that by default takes 1 elapsed week to do. You can specify 1ew
which is 1 week of 7x24 hours ignoring any calendar.

--

Rod Gill
Microsoft MVP for Project

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

 

[Jan De Messemaeker]

Hi,

Yes. Use the DateDiff function in a formula.
HTH

--
Jan De Messemaeker
Microsoft Project Most Valuable Professional
+32 495 300 620
For availability check:
http://users.online.be/prom-ade/Calendar.pdf

Rod,

Ok - duration measures work(ing days), not the time between events (like
start, finish) - that's a subtle point of defining terms that I missed.
However, folks reading the printout are even less likely to grasp the
notion. Can I customize a field to show that the time between start and
end is n days, where n is not necessarily an integer?

Norm

 

[Norman Goldsmith]

Trevor,

"They", including me, have been trained in (US) English where duration is
defined as:
Noun
the length of time that something lasts [Latin durare to last]

When "they" see duration alongside of dates, "they" assume the noun refers
to time not work effort. When "they" look at a Gantt chart, "they" want to
know how long the task lasts, without having to figure it out from start and
end times or even the bar length. Now that Gill has pointed out the
specialized (and fundamental) usage of duration in Project, it remains my
obligation to answer their question. Jan has kindly provided the function
needed to do that. I'll label the field elapsed time, which will answer the
reasonable question of how long will it take.

Norm

If the people reading it don't understand it, why do they want to see it
and why do you have to give it to them?
This matter of how duration is measured is sensible and rather
fundamental. Maybe you could just explain it to them.
--
Trevor Rabey
0407213955
61 8 92727485
PERFECT PROJECT PLANNING
www.perfectproject.com.au

 

[Steve House [MVP]]

The noun DOES refer to time, not work effort. It's "the length of time that
something lasts" but non-working time isn't counted - since we can never
schedule work to take place during the non-working hours, they might as well
not exist and as far as duration time numbers are concerned, they don't.
That's not the same thing as work effort. If I have a task that starts
Monday at 8am and ends Friday at 5pm, its duration is 40 hours, not the 105
clock hours that elapse between those two times. If 1 resource is working
full-time on the task, the work effort is 40 man-hours - the two are the
same. But if two resources are working on it, the work effort is 80
man-hours, with three resources it's 120 man-hours, etc while the duration
remains at 40 hours. If one resource is half-time on it, the work effort is
20 man-hours, yet the duration remains at 40.

Every discipline has its own specialized vocabulary where words may carry a
different meaning than they do in everyday speech.
--
Steve House [Project MVP]
MS Project Trainer & Consultant
Visit http://project.mvps.org/faqs.htm for the FAQs

Trevor,

"They", including me, have been trained in (US) English where duration is
defined as:
Noun
the length of time that something lasts [Latin durare to last]

When "they" see duration alongside of dates, "they" assume the noun refers
to time not work effort. When "they" look at a Gantt chart, "they" want to
know how long the task lasts, without having to figure it out from start
and end times or even the bar length. Now that Gill has pointed out the
specialized (and fundamental) usage of duration in Project, it remains my
obligation to answer their question. Jan has kindly provided the function
needed to do that. I'll label the field elapsed time, which will answer
the reasonable question of how long will it take.

Norm

If the people reading it don't understand it, why do they want to see it
and why do you have to give it to them?
This matter of how duration is measured is sensible and rather
fundamental. Maybe you could just explain it to them.
--
Trevor Rabey
0407213955
61 8 92727485
PERFECT PROJECT PLANNING
www.perfectproject.com.au

 

[Norman Goldsmith]

Steve,

I stand corrected on my statement about work effort in the last post - I
realized it was wrong several milliseconds after hitting send. I also
understand that disciplines, and programs, have special meanings for some
terms. It also seemed logical, and necessary, for me to create a week-end
work calendar for tasks that should only occur on the weekend.

However, seems illogical to me that the summarization of work that properly
takes place over a seven day period requires the user to assign a special
calendar to the summary in order to display the total time encompassed by
the summary. But, I suppose that's just another case of specialized
vocabulary, since it's not really a summary, it's a roll-up. [Does not
explain the fact that the Project SUMMARY Task follows the same logic.]

However, since Project's logic says that roll-ups must obey their own
calendar, I'll create the computation that my users are looking for.

Thanks,
Norm

The noun DOES refer to time, not work effort. It's "the length of time
that something lasts" but non-working time isn't counted - since we can
never schedule work to take place during the non-working hours, they might
as well not exist and as far as duration time numbers are concerned, they
don't. That's not the same thing as work effort. If I have a task that
starts Monday at 8am and ends Friday at 5pm, its duration is 40 hours, not
the 105 clock hours that elapse between those two times. If 1 resource is
working full-time on the task, the work effort is 40 man-hours - the two
are the same. But if two resources are working on it, the work effort is
80 man-hours, with three resources it's 120 man-hours, etc while the
duration remains at 40 hours. If one resource is half-time on it, the
work effort is 20 man-hours, yet the duration remains at 40.

Every discipline has its own specialized vocabulary where words may carry
a different meaning than they do in everyday speech.
--
Steve House [Project MVP]
MS Project Trainer & Consultant
Visit http://project.mvps.org/faqs.htm for the FAQs

Trevor,

"They", including me, have been trained in (US) English where duration is
defined as:
Noun
the length of time that something lasts [Latin durare to last]

When "they" see duration alongside of dates, "they" assume the noun
refers to time not work effort. When "they" look at a Gantt chart, "they"
want to know how long the task lasts, without having to figure it out
from start and end times or even the bar length. Now that Gill has
pointed out the specialized (and fundamental) usage of duration in
Project, it remains my obligation to answer their question. Jan has
kindly provided the function needed to do that. I'll label the field
elapsed time, which will answer the reasonable question of how long will
it take.

Norm

If the people reading it don't understand it, why do they want to see it
and why do you have to give it to them?
This matter of how duration is measured is sensible and rather
fundamental. Maybe you could just explain it to them.
--
Trevor Rabey
0407213955
61 8 92727485
PERFECT PROJECT PLANNING
www.perfectproject.com.au

Rod,

Ok - duration measures work(ing days), not the time between events
(like start, finish) - that's a subtle point of defining terms that I
missed. However, folks reading the printout are even less likely to
grasp the notion. Can I customize a field to show that the time between
start and end is n days, where n is not necessarily an integer?

Norm

"Rod Gill" <rodATproject-systemsDOTcoDOTnz> wrote in message
No! Duration is always in working days. So 1w by default is 40 working
hours that by default takes 1 elapsed week to do. You can specify 1ew
which is 1 week of 7x24 hours ignoring any calendar.

--

Rod Gill
Microsoft MVP for Project

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



MS Project 2002 SP-1, Windows XP

Project with two tasks, project starts on 2 February. Standard Gantt
chart displayed, entry table.

Task 1, duration 5 days, Start & End dates (copied & pasted in
directly) "February 2, 2009 8:00 AM" "February 6, 2009 5:00 PM", no
calendar, sole subtask of a summary that exactly repeats start, end
and duration.

Task 2, duration 2 days (displayed), Start & End dates "February 7,
2009 8:00 AM" "February 8, 2009 5:00 PM", uses Weekend Calendar where
only Saturday and Sunday are workdays. Sole subtask of a summary that
shows the identical start and end dates but shows duration of 0 days!

Task 2 is linked FS to Task 1.

At the highest level another summary task, that has the two summary
tasks as subtasks. This task has start & end dates of "February 2,
2009 8:00 AM" "February 8, 2009 5:00 PM". It has no assigned calendar
and shows that the duration is 5 days. Turning on the Project Summary
task repeats the information including the 5 day duration despite the
span of 7 days.

On the Gantt chart side, all of the bars are of the correct length
and placement.

In the real project, tasks using the two calendars will be placed
under a single summary task. Is there a fix so that the duration
field reports the elapsed time correctly?

Thanks,

 

[Norman Goldsmith]

Jan,

Used the formula DateDiff("d",[Start],[Finish])+1, as the formula for a text
field. The answers turn out to be integer values but are certainly good
enough for my audience. Those who want greater precision can look in the
finish field to get the time of day.

Thanks,
Norm

Hi,

Yes. Use the DateDiff function in a formula.
HTH

--
Jan De Messemaeker
Microsoft Project Most Valuable Professional
+32 495 300 620
For availability check:
http://users.online.be/prom-ade/Calendar.pdf