Trying to understand MSP 2003/2000 behavior

[david]

I am trying to understand certain MSP behavior which I have seen with both
2000 and 2003.

The first thing I am trying to understand is why Project splits the end of
fixed duration tasks in strange ways. Here is what I have done:

Settings:
Work starts on: Sunday
Default start time: 12:00 AM
Default end time: 12:00 AM
Hours per day: 24.00
Hours per week: 168.00
Days per month: 30

24 hr project calendar

Resource #1
Standard calendar
No availability configured

Task #1
Start date: 5/16/07
Duration: 5 days
Work: 0
Constraint date: 5/16/07
Constraint type: Start no earlier than
Predecessor(s): none
Successor(s): none
Lag: none
Type: fixed duration, effort-driven

Task #2
Identical to task #1.

---

After setting this project up I assign resource #1 to both tasks. The work
field for both tasks is now 24 hrs. Task #1 starts on Wednesday and ends
on Monday. Task #2 starts on Monday and ends on Saturday. Resource #1 is
scheduled for only 1 hr of work on Monday (for task #2). Task #2 splits on
Thursday after 7 hours of work and continue to show split (periods instead
of a bar on the Gantt chart) until Saturday, at which point the task ends.

Why does task #2 split at the end?

Why doesn't task 2 start on Monday at 8AM?


I have found that changing the tasks' start date changes this behavior. If
I remove the resources and start both tasks on Monday 5/14/07 and assign
resource #1 to task #1 then 40 hrs of work are performed on it over 5 days.
If I then assign resource #1 to task #2, 40 hrs of work will be done on it
as well but task #2's duration changes to 7 days. The task starts at 4PM
on Monday and continues until the following Monday on which 7 hrs of work
are scheduled. The "end split" no longer shows up.

Why does the duration of task #2 (fixed duration) change to 7 days?

I entered this last project setup again to be sure I described it right. I
accidentally created the tasks as "Fixed Units" and after assigning
resource #1 to task #1 the task spreads out to over 2 weeks so that 120 hrs
of work are done.

Why doesn't the duration change here to show how many days have gone by
between the start and finish dates? I thought that a 24 hr project
calendar would make a 5d duration 5 whole days.

I've worked with elapsed time before but in this case if I use 5 edays
instead then the resource is scheduled to work 24 hrs a day instead of 8
hrs per day as its calendar is configured.

I feel many of my problems are the result of trying to use 24 hr calendars
along with standard calendars. I do not see a way around this as I am
trying to schedule a lab which contains equipment that does work 24/7 as
well as shifts of people.

Thanks for any help,

David

 

[Mike Glen]

Hi David,

Welcome to this Microsoft Project newsgroup

Have you set Project/Project Information to show the Project Start Date as
1200am on 16 May? If not, I suspect it's starting at the default time of
0800 on the first day.

FAQs, companion products and other useful Project information can be seen at
this web address: http://project.mvps.org/faqs.htm

Hope this helps - please let us know how you get on

Mike Glen
MS Project MVP
See http://tinyurl.com/2xbhc for Project Tutorials

 

[David]

Hi David,

Welcome to this Microsoft Project newsgroup

Have you set Project/Project Information to show the Project Start Date as
1200am on 16 May? If not, I suspect it's starting at the default time of
0800 on the first day.

Thanks for the welcome Mike. I hope to learn a bit here!

I checked the project start time, it is 1200am on 16 May. I believe it
is starting at 0800 on the first day because the resource is using a
standard calendar.

The two things I would really like to understand before anything else
are why the second task ends up splitting at the end in the strange way
it does and why the second task starts at 4pm on Monday and only has one
hour of work on that day.

Using different dates makes quite a difference too; using the same
weekday on other weeks produces different results (often being exactly
what I expect in the first place).

I would really appreciate some help with either of those questions (the
first two in my original post). As is right now I am hesitant to do
much of anything with Project because it seems after studying and
working with it for a few months I can not explain things that are
happening with only two tasks and one resource involved!!

Thanks again,

David

 

[David]

Since I'm noticing that different dates produce different effects I am
doubting anyone will be able to explain this without reproducing it in
Project. I've done it with 2000 and 2003. If someone could do this and
give me their thoughts I would appreciate it (I'm interested if newer
versions of Project produce the same results too).

It involves creating two tasks and one resource, I've tried to keep it
as simple as possible. I'll focus only on these first two questions (at
the end) for the time being- I had others in my original post.

Thanks,

David

 

[Jan De Messemaeker]

I'll look at it, OK but rest assured of one thing: you will have the same
resulyts in all recent versions

 

[David]

I'll look at it, OK but rest assured of one thing: you will have the same
resulyts in all recent versions

I believe my problems are from mixing the 24hr and standard calendars.

I don't see why MSP has separate calendars for the entire project,
tasks, and resources when they conflict so much (my list of strange
behaviors has been growing).

One things I have not tried is mixing the calendars in a project but
keeping the task/resource calendars the same (i.e. if the task is 24hr,
the resource must be 24hr as well). I will be trying this in the future
though so I'll post back with my results.

David

 

[Steve House]

The Project calendar is the "Master Clock" for the project, the one to be
used when no other calendar governs. IMHO, the Project calendar should
reflect the working hours of a "typical" generic resource, not the overall
hours of the firm. If I have a task that requires 24 hours of work, it
likely will NOT be done in a continuous 24 hour period. I'm goiung to
assign it to one guy eventually and it will go for 3 shifts of 8 hours each.
That might end up on day shift or on swing shift or on grave, but regardless
it won't run for 24 hoiurs straight. Thus the 24 hour calendar is not
appropriate to control where its placed in the schedule prior to assigning
the resource and refining it to the exact start and end times during the day
it will follow. But tasks don't happen unless the specific resources
required are there to work on them. And usually the resource schedules are
not very flexible, you usually schedule the task for when the resources are
going to be there, and you don't reschedule the resources around when you
want the tasks to be done. So when you assign a resource to a task, the
working time schedule of that specific resource will govern when the task
can happen. But there are some situations where you do need the task to be
scheduled at some unusual time and so it is possible to create a task
calendar to serve as an exception to the normal situation.

 

[David]

Sounds like a great description of how it should work. If you can find
a way to explain how it really does work now (see original post), I'd be
thrilled.

 

[Jan De Messemaeker]

Hi David,

I looked at the first of your "mysteries" and here is the explanation.
I hope the understanding may help you to undestand the others, too.

When i do exactly as you are told, Task 2 DOES NOT start on Monday - why
would it.
I have to assume that you entered a Start Not earlier than constraint for
Monday.
I also assume (it would have been better if you had given exactly what you
did) that you entered the constraint date as only the date, not the hours.
Well then, Project cannot apply the constraint as such, because it schedules
everything by the minute.
It has to complete the constraint date with a constraint time, so it takes
the default of 12 AM.
That is why the tasks starts at 12 AM and not at 8AM.

It then schedules 4 hrs of work (the afternoon shoft of the resource) then 8
hrs on Tue 8 hrs on Wed and the final 4 hrs on Thu.
Now against all odds you have told Project that it should not change
duration, so the task cannot but end on Saturday, 12AM
Thus the time between the end of Work (Thu 5PM) and the end of the task (Sat
12AM) is represented by a split.

Hope this helps

 

[David]

That would make sense but Task 2 is exactly the same as Task 1- Start No
Earlier than 5/16/07. Also, the task starts at 4PM on Mon, not 12AM or 8AM.
Here are two screenshots I've posted to try to help explain the problem, I
will provide something more detailed later...

http://img256.imageshack.us/img256/793/projectexamplemm0.jpg

Here you can see the "split" at the end of the task. Again, both tasks were
originally scheduled to start on 5/16/07. Other settings can be read below.

http://img509.imageshack.us/img509/7881/projectexample2zk6.jpg

Here the allocation of the resources can be seen. Both resources are on
standard calendars and the task is on a 24/7 calendar. Notice the resource
only works 1 hour on Monday, 7 hours on Thursday and 0 hours on Friday.
This happens to be the same number of hours that the resource works on Task
1!

These effects seem to change with different start dates. If I use the
Wednesday of a different week I get different results...

David

 

[Jan De Messemaeker]

Hi,

Why do you want me to guess what you entered as parameters?
If I enter the parameters you clam, the task always starts at 12AM.
Don't look for a mysterious why in Project, look for the setting you may
have entered.
Unless you have a buggy version (wouldn't know which one would do this)

I did explain the split so no need to come back to that.
HTH

 

[David]

Jan,

I do not expect you to guess the parameters, they are exactly as I first
described (still being quoted in this post). Task 1 and Task 2 are
described in there (settings for both are identical). You said you assume a
"start not earlier than" constraint on Task 2- the constraint is Start As
Soon As Possible and the constraint date is 5/16/07, the same as Task 1.

Task 2 does not start at 12:00AM or 8:00AM for me, the two times you
mentioned. Also, Task 2 does not have 4 hours of work on Monday as you
mentioned- it has only 1 hour on Monday (see the pictures I posted).

The tasks are fixed duration, I understand that the duration can not change,
but why doesn't the resource keep working on the task for the remainder of
the week? It stops on Wednesday! If I started a 5d duration task on Monday
and assigned a standard calendar resource it works all week, 40 hours.

Task 2 is scheduled for Mon-Fri, that should be 40 hours using a standard
resource calendar! If you change Task 1 to start on a Monday it receives 40
hours of work- this is why I wonder why Task 2 does not receive 40 hours of
work- it starts on a Monday. It only receives 24 hours of work- 24 hours of
work matches Task1. Task 1 spans the weekend, I understand why there would
be no work on Saturday and Sunday. If this doesn't explain why I am looking
for an explanation on the split then I can give you exact steps as to what
I'm doing for multiple cases and you can see how the split shows up
sometimes and not other times (for instance, if you use a different
Wednesday then 5/16/07 sometimes the results are different).

I believe I listed all the parameters in my very first post. As a
programmer I understand that a single parameter could change the outcome. I
have re-entered this project probably about a hundred times by now, always
with the same results. I tried on a fresh install of Project. I would be
suspecting a buggy version myself but since I get the same results at home
as I do at work (two different versions), I am doubting it's my install.

Thank you for working with me on this Jan, I understand if you are
frustrated to the point of not wanting to help anymore! I'm almost
frustrated to the point of not asking for any more help but I still have
hope.

David

 

[Jan De Messemaeker]

Hi,

OK, one by one.
What is the constraint of task 2 exactly (I mean including time of day)
You can't discuss the result in terms of time of day without giving the
constraint in the same units can you?

Better dtill, can you send the file to
jandemesATprom-adeDOTbe
That will speed up our conversation by a factor!

 

[Jan De Messemaeker]

Hi All,

To (hopefully) end this:
After investigating the file, I agree that there is a bug in Leveling in
this case.
All other "oddities" have been explained and work as expected.

I also opened the file in 2007 and both the oddities and the bug are gone.
Hope this helps,

 

[David]

Thanks Jan,

I'm sorry to find there isn't a simple explanation (like "you forgot to
set...") but glad to know I'm not crazy.

Very glad to hear this works in Project 2007. I have a list of other
problems that I run into with 24/7 and standard calendars, I will see how
those work out with MSP 2007 too.

Regards,

David