A Fixed duration task changes duration

M

Michele

I have experimented that sometimes Project changes the duration of a fixed
duration task.
I'm trying to investigate when it happens, that is under what particular
circumstance i can make Project repeat this behaviour.
Yesterday i was almost sure about having found all the specific
circumstances in which Project changes the duration of a fixed duration task
but today i tried again to apply those cases and the duration still remained
the same.
Since that a software behaviour can't be randomly i ask you all if anyone
can indicate me the specific cases when Project changes the duration of a
fixed duration task.
I specify that i have uncheked the levels individual assignments option.
Thanks for any advice
Michele
 
M

Michele

Surprisingly the thing seems to be related to the show indicators and option
buttons section of the Project general option.
If i uncheck all the relative fields, the duration of a fixed duration task
doesn't change.
On the opposite if i leave all the above fields checked and, for example, i
change the work for a specific assignment(let's put i have only one
assignment but the same happens also for multiple resources assignments), if
i select the triangle indicator and click the default selected option and
then i change the finish date of the assignment(decreasing it) then the
duration of the task decreases the same.
If, instead, i do not select the triangle indicator and than i change the
finish date of the assignment(decreasing it) then the duration of the task
doesn't change.
I wonder why.
I would be very grateful to receive any comment or suggestion.
Thanks a lot
Michele

"Michele" ha scritto:
 
J

JulieS

Hi Michele,

I suggest working with the Task Form open underneath the Gantt Chart
(Window>Split). This displays a view called the Task Entry view. If you
change work or units in the bottom pane (Task Form) the feedback indicators
do not appear and I think you'll find things are more predictable.

That being said, yes, there are circumstances when a fixed duration task
will change duration. If you have a resource assigned to a fixed duration
task and then change the resource's calendar to add nonworking time during
the period when the task is scheduled, Project will change the task
duration. As resources may only work during time defined as working time,
Project has no option other than to increase the task duration to reschedule
the work.

I hope this helps. Let us know how you get along.

Julie
 
M

Michele

My problem is not about how i can obtain a certain result, my aim is to deep
understand the whole behaviour of Ms Project so that i can automate as much
as it is possible, through vba, the data entry side and the maintaining side
of a project.
You understand that i can't spend many hours(Hope not so many..) of
programming and ,once done, realize that i need to rewrite the code because i
didn't predict a Ms project behaviour in some specific circumstance.
Anyway, about what you say regarding calendar i totally agree with you but
it is different from the case i described in my first question.
Thank you Julie
Best regards
Michele
"JulieS" ha scritto:
 
J

JulieS

Hi Michele,

You are welcome and thanks for the feedback.

To delve a bit deeper, in your second post you note: "then i change the
finish date of the assignment(decreasing it) then the duration of the task
decreases the same". I am puzzled.

If I create two fixed duration tasks and link them Finish-to-Start, and drop
work, in the feedback indicator the default option is "Decrease the hours a
resource works per day, so the duration remains the same" the unit
assignment drops as expected. If I then try to change the finish date of
the successor task, I am unable to. If I remove the link (all tasks now
start on the start date of the project), when I change the finish date, the
start date moves and I create a finish no earlier than constraint.

As you have discovered, what Project does in entirely dependant upon the
specific set of circumstances involved (what kind of task, what was changed,
then when was changed, etc.)

I realize this isn't much help but trying to predict what every person will
do in every set of circumstances is impossible.

I am by no means skilled in programming, so perhaps if you could post
specifically what you are trying to automate with your code, others can
assist or give much better guidance than I.

Julie
 
M

Mike Glen

Hi Michele,

PS - in the devloper newsgroup, please. Please see FAQ Item: 24. Project
Newsgroups. FAQs, companion products and other useful Project information
can be seen at this web address: http://project.mvps.org/faqs.htm

Mike Glen
Project MVP
 
S

Steve House [Project MVP]

What version of Project are you using? Can you post EXACTLY what you are
changing and where you are changing it? You mention in this post that when
you change the work, then change the finish date of the assignment
(assignment finish and task finish are different concepts, by the way) you
get a triangle indicator. When I do it in Project 2003 Pro I don't get an
indicator at all. You also reference a "show indicators" in the option
button section of the Project general options. Again, where are you talking
about? In my Project 2003 Pro desktop, the Tools menu, Options selection,
General tab doesn't make any reference to "show indicators."

There are several rthings to remember to help you understand what's going
on. First is just what "fixed duration" means. It does NOT mean the
duration can never change under any circumstance. Remember the "prime
directive" is W=D*U and this mathematical identity will never, ever, be
violated no matter what. Any linear equation is of the general formula
Y=mX*b where X is the independent variable, Y is the dependent, and m and b
are constants. In Project, b=zero so the equation becomes Y=mX. When a
task is designated "fixed xxx" it serves to designate which item in the work
equation, Work, Duration, or Units is to be treated as the constant,
allowing you to arbitrarily choose which of the other two terms will be
changed (becoming the X) and thus defining which term is to be calculated.
"Fixed duration" means that when changing Work, Units are recalculated and
when changing Units, Work is recalculated. If you have the task as "fixed
duration" and manually force a change to duration, Project reverts to
"fixed units" behaviour and recalculates the Work value.

Second, remember that duration is defined as the number of working time
units AS DEFINED IN THE CALENDAR THAT GOVERNS THE TASK that occur between
when work is first performed and when it is finished. If you change the
finish date without changing the start date, the duration must change by
definition since the difference between start date and finish date in
working time units IS the duration. If a resource hasn't been assigned to
the task, the calendar that defines which minutes out of the day count for
duration is the Project calendar. When a resource is assigned, the calendar
that determines which minutes count is the resource calendar. When a task
is split, the minutes inside the split are removed from consideration So a
task that goes one week, stands down for a week, and then resumes for
another week has a 2 week duration, not 3. However, consider two resources
being assigned with each doing 1 week work. The first works for a week and
then goes away. A week passes with no activity. Then the 2nd resource come
in and works a week and the task is finished. In this task the duration is
3 weeks, not two. Resource "A"s calendar governs the first week, the
Project Calendar governs the 2nd, and Resource "B"'s governs the 3rd.

You mention in another post that you are trying to automate data entry with
VBA. Why are you trying to automate this in the first place? Setting of
durations and units should be a decision made by the user, not the software.
Project should not attempt to automate decisions more properly made by the
managers responsible for the successful completion of the project nor should
estimating the fundamental project parameters of duration, work, and units
be something left to mechanical inputs by data entry clerks. Project is an
aid in the decision making process best used by decision makers, not simply
a tool to document projects passively.
--
Steve House [MVP]
MS Project Trainer & Consultant
Visit http://www.mvps.org/project/faqs.htm for the FAQs
 
M

Michele

Hi Steve.
It's nice to meet you again.
I'm using the standard version of Project 2003.
About the options: Tools/Options/Interface: Show Resource Assignment
Indicators, Show Edit to Start Finish dates, Show Edits to work units
duration indicators.
I try to be more clearly about what i mean; let's start from the beginning.
I create a new effort driven fixed duration task, let's say its name is
"Test".
I Change the duration field of the "Test" task from the default 1 day to 2
days.
I leave blank, that is 0 hours, the work field of the "Test" task.
The above task is not linked to any other tasks and it has a constraint
equal to "As soon as possible".
Let's say that the Project start date is equal to Monday 01/30/06, so the
task "Test" starts on monday 01/30/06 and finishes on tuesday 01/31/06.
Go in the Tools/Options/Interface and check all the options i was talking
about at the beginning of this reply.
Now create only one 100% units assignment for the "Test" task, let's call it
"John".
So, now, the task duration is obviously still 2 days, the total amount of
"Test" work is equal to 16 hours and John will have to spend on it 8 hours on
monday 01/30/06 and 8 hours on tuesday 01/31/06.
Now change the "John" assignment work field from 16 hours to 8 hours and it
should appear a green smart tag on the top left angle of it.
Click on the green smart tag and than click on the default selected
option.(That is Decrease resource units)
Now change the "John" assignment finish field from tuesday 01/31/06 to
monday 01/30/06 and, as a result, you can see that the "Test" task finish
field changes too simultaneously and automatically from tuesday 01/31/06 to
monday 01/30/06 and consequently the "Test" task duration field changes
simultaneously and automatically from 2 days to 1 day.
Now repeat exactly the process i described above but without checking the
above mentioned options in Tools/Options/Interface, that is making them
unchecked.
Now, as a result, you shouldn't have any green smart tag when you change the
"John" assignment work field.
The result of leaving unchecked the options is that the "Test" task finish
field doesn't change too automatically from tuesday 01/31/06 to monday
01/30/06 but it remains tuesday 01/31/06 and consequently the "Test" task
duration field doesn't change simultaneously and automatically from 2 days to
1 day but it remains 2 days and what changes is only the "John" assignment
duration that becomes 1 day.
If you than go on th Gant chart you can now see that in the "Test" task
there is a split that goes from the end of 01/30/06 to the end of 01/31/06.
First of all, i'd like to know if you , Steve, and other guys/gals can
experiment the same behvaiour repeating my example and, if the answer is yes,
i really would like to know what is, in your opinion, the most desiderable
behaviour between the two described above.
The point, i think, is in how, in the case of a fixed duration task,
Microsoft Project applies the basic scheduling formula Duration = Work/Units.
What i mean is that, while i have no problems in determining which are the
variables of the above formula in a fixed units or fixed work task because
both units and work are pure assignments editable parameters and in these two
cases the duration variable is always equal to the assignment/s
duration(because when you have at least one assignment the formula applies to
the assignment/s and not to the task) , i am absoultely not sure about how i
can determine the three variables in a fixed duration task, or , better, i
really wish to know how Project handle the three variables in a fixed
duration task with at least one assignment.
Really thank you Steve for your and others reply.
Best regards
Michele






If i uncheck all the relative fields, the duration of a fixed duration task
doesn't change.
On the opposite if i leave all the above fields checked and, for example, i
change the work for a specific assignment(let's put i have only one
assignment but the same happens also for multiple resources assignments), if
i select the triangle indicator and click the default selected option and
then i change the finish date of the assignment(decreasing it) then the
duration of the task decreases the same.
If, instead, i do not select the triangle indicator and than i change the
finish date of the assignment(decreasing it) then the duration of the task
doesn't change

"Steve House [Project MVP]" ha scritto:
 
J

John M.

INHMO perhaps the question should be "why are you changing the duration on a
fixed duration task?" By definition, it is then no longer a fixed duration
task. What is the outcome you are looking for?

The task type should be viewed as a dynamic setting for a task - based on
what change you are making to the task and what outcome you want, you set
it. By changing the finish date on a task, you are changing the duration.
Changing the duration on a fixed duration task will result in MS Project
recalculating the work (keeping assignment units fixed). I would simply set
the task to fixed units first, this way it is very clear to me that I am
changing duration, units is fixed, so MS Project will recalculate the work.
In both of the cases you list below, if you change the task to fixed units
even after going through all your steps, it will reset the task duration to
match the assignment duration.

I can honestly say that I don't find myself setting the start or finish
dates on tasks or assignments very often at all, as the former will set
constraints on tasks that I generally don't want imposed. Perhaps you
should review the process that you are using for planning and tracking work
plans (again reviewing the FAQ's and Mike Glen's series). I don't believe
you will be successful in trying to plan for every permutation of inputs
from the project managers. Choose a standard and ensure everybody is aware
of it.

Good luck.

John M.



Michele said:
Hi Steve.
It's nice to meet you again.
I'm using the standard version of Project 2003.
About the options: Tools/Options/Interface: Show Resource Assignment
Indicators, Show Edit to Start Finish dates, Show Edits to work units
duration indicators.
I try to be more clearly about what i mean; let's start from the
beginning.
I create a new effort driven fixed duration task, let's say its name is
"Test".
I Change the duration field of the "Test" task from the default 1 day to 2
days.
I leave blank, that is 0 hours, the work field of the "Test" task.
The above task is not linked to any other tasks and it has a constraint
equal to "As soon as possible".
Let's say that the Project start date is equal to Monday 01/30/06, so the
task "Test" starts on monday 01/30/06 and finishes on tuesday 01/31/06.
Go in the Tools/Options/Interface and check all the options i was talking
about at the beginning of this reply.
Now create only one 100% units assignment for the "Test" task, let's call
it
"John".
So, now, the task duration is obviously still 2 days, the total amount of
"Test" work is equal to 16 hours and John will have to spend on it 8 hours
on
monday 01/30/06 and 8 hours on tuesday 01/31/06.
Now change the "John" assignment work field from 16 hours to 8 hours and
it
should appear a green smart tag on the top left angle of it.
Click on the green smart tag and than click on the default selected
option.(That is Decrease resource units)
Now change the "John" assignment finish field from tuesday 01/31/06 to
monday 01/30/06 and, as a result, you can see that the "Test" task finish
field changes too simultaneously and automatically from tuesday 01/31/06
to
monday 01/30/06 and consequently the "Test" task duration field changes
simultaneously and automatically from 2 days to 1 day.
Now repeat exactly the process i described above but without checking the
above mentioned options in Tools/Options/Interface, that is making them
unchecked.
Now, as a result, you shouldn't have any green smart tag when you change
the
"John" assignment work field.
The result of leaving unchecked the options is that the "Test" task finish
field doesn't change too automatically from tuesday 01/31/06 to monday
01/30/06 but it remains tuesday 01/31/06 and consequently the "Test" task
duration field doesn't change simultaneously and automatically from 2 days
to
1 day but it remains 2 days and what changes is only the "John" assignment
duration that becomes 1 day.
If you than go on th Gant chart you can now see that in the "Test" task
there is a split that goes from the end of 01/30/06 to the end of
01/31/06.
First of all, i'd like to know if you , Steve, and other guys/gals can
experiment the same behvaiour repeating my example and, if the answer is
yes,
i really would like to know what is, in your opinion, the most desiderable
behaviour between the two described above.
The point, i think, is in how, in the case of a fixed duration task,
Microsoft Project applies the basic scheduling formula Duration =
Work/Units.
What i mean is that, while i have no problems in determining which are the
variables of the above formula in a fixed units or fixed work task because
both units and work are pure assignments editable parameters and in these
two
cases the duration variable is always equal to the assignment/s
duration(because when you have at least one assignment the formula applies
to
the assignment/s and not to the task) , i am absoultely not sure about how
i
can determine the three variables in a fixed duration task, or , better, i
really wish to know how Project handle the three variables in a fixed
duration task with at least one assignment.
Really thank you Steve for your and others reply.
Best regards
Michele






If i uncheck all the relative fields, the duration of a fixed duration
task
doesn't change.
On the opposite if i leave all the above fields checked and, for example,
i
change the work for a specific assignment(let's put i have only one
assignment but the same happens also for multiple resources assignments),
if
i select the triangle indicator and click the default selected option and
then i change the finish date of the assignment(decreasing it) then the
duration of the task decreases the same.
If, instead, i do not select the triangle indicator and than i change the
finish date of the assignment(decreasing it) then the duration of the task
doesn't change

"Steve House [Project MVP]" ha scritto:
What version of Project are you using? Can you post EXACTLY what you are
changing and where you are changing it? You mention in this post that
when
you change the work, then change the finish date of the assignment
(assignment finish and task finish are different concepts, by the way)
you
get a triangle indicator. When I do it in Project 2003 Pro I don't get
an
indicator at all. You also reference a "show indicators" in the option
button section of the Project general options. Again, where are you
talking
about? In my Project 2003 Pro desktop, the Tools menu, Options
selection,
General tab doesn't make any reference to "show indicators."

There are several rthings to remember to help you understand what's going
on. First is just what "fixed duration" means. It does NOT mean the
duration can never change under any circumstance. Remember the "prime
directive" is W=D*U and this mathematical identity will never, ever, be
violated no matter what. Any linear equation is of the general formula
Y=mX*b where X is the independent variable, Y is the dependent, and m and
b
are constants. In Project, b=zero so the equation becomes Y=mX. When a
task is designated "fixed xxx" it serves to designate which item in the
work
equation, Work, Duration, or Units is to be treated as the constant,
allowing you to arbitrarily choose which of the other two terms will be
changed (becoming the X) and thus defining which term is to be
calculated.
"Fixed duration" means that when changing Work, Units are recalculated
and
when changing Units, Work is recalculated. If you have the task as
"fixed
duration" and manually force a change to duration, Project reverts to
"fixed units" behaviour and recalculates the Work value.

Second, remember that duration is defined as the number of working time
units AS DEFINED IN THE CALENDAR THAT GOVERNS THE TASK that occur between
when work is first performed and when it is finished. If you change the
finish date without changing the start date, the duration must change by
definition since the difference between start date and finish date in
working time units IS the duration. If a resource hasn't been assigned
to
the task, the calendar that defines which minutes out of the day count
for
duration is the Project calendar. When a resource is assigned, the
calendar
that determines which minutes count is the resource calendar. When a
task
is split, the minutes inside the split are removed from consideration So
a
task that goes one week, stands down for a week, and then resumes for
another week has a 2 week duration, not 3. However, consider two
resources
being assigned with each doing 1 week work. The first works for a week
and
then goes away. A week passes with no activity. Then the 2nd resource
come
in and works a week and the task is finished. In this task the duration
is
3 weeks, not two. Resource "A"s calendar governs the first week, the
Project Calendar governs the 2nd, and Resource "B"'s governs the 3rd.

You mention in another post that you are trying to automate data entry
with
VBA. Why are you trying to automate this in the first place? Setting of
durations and units should be a decision made by the user, not the
software.
Project should not attempt to automate decisions more properly made by
the
managers responsible for the successful completion of the project nor
should
estimating the fundamental project parameters of duration, work, and
units
be something left to mechanical inputs by data entry clerks. Project is
an
aid in the decision making process best used by decision makers, not
simply
a tool to document projects passively.
 
S

Steve House [Project MVP]

I saee what you're talking aobut now. When you change a date you are
changing the duration, by definition. When the task is set as fixed
duration yet you change the duration, project gets confused and it is asking
you whether it should treat this edit as if the task was fixed units or
fixed work.

As an aside, I have a major issue with the use of fixed duration in most
circumstances. That to me implies the task takes a specific length of time
to complete regardless of the efforts put into it and few deliverables work
that way. If we have a timed test that runs for 24 hours, well that is
fixed duration. But most tasks are on the order of "build 1000 widgets" and
they will last however long it takes to build 1000 widgets. As conditions
change the amount of clock time it requires to build those widgets will also
change. But the task doesnm't quit at the end of some arbitraru time if at
that time you only have 900 widgets. Duration is your estimate of the time
the work WILL take, not the time you have allotted for it to take.
--
Steve House [MVP]
MS Project Trainer & Consultant
Visit http://www.mvps.org/project/faqs.htm for the FAQs



Michele said:
Hi Steve.
It's nice to meet you again.
I'm using the standard version of Project 2003.
About the options: Tools/Options/Interface: Show Resource Assignment
Indicators, Show Edit to Start Finish dates, Show Edits to work units
duration indicators.
I try to be more clearly about what i mean; let's start from the
beginning.
I create a new effort driven fixed duration task, let's say its name is
"Test".
I Change the duration field of the "Test" task from the default 1 day to 2
days.
I leave blank, that is 0 hours, the work field of the "Test" task.
The above task is not linked to any other tasks and it has a constraint
equal to "As soon as possible".
Let's say that the Project start date is equal to Monday 01/30/06, so the
task "Test" starts on monday 01/30/06 and finishes on tuesday 01/31/06.
Go in the Tools/Options/Interface and check all the options i was talking
about at the beginning of this reply.
Now create only one 100% units assignment for the "Test" task, let's call
it
"John".
So, now, the task duration is obviously still 2 days, the total amount of
"Test" work is equal to 16 hours and John will have to spend on it 8 hours
on
monday 01/30/06 and 8 hours on tuesday 01/31/06.
Now change the "John" assignment work field from 16 hours to 8 hours and
it
should appear a green smart tag on the top left angle of it.
Click on the green smart tag and than click on the default selected
option.(That is Decrease resource units)
Now change the "John" assignment finish field from tuesday 01/31/06 to
monday 01/30/06 and, as a result, you can see that the "Test" task finish
field changes too simultaneously and automatically from tuesday 01/31/06
to
monday 01/30/06 and consequently the "Test" task duration field changes
simultaneously and automatically from 2 days to 1 day.
Now repeat exactly the process i described above but without checking the
above mentioned options in Tools/Options/Interface, that is making them
unchecked.
Now, as a result, you shouldn't have any green smart tag when you change
the
"John" assignment work field.
The result of leaving unchecked the options is that the "Test" task finish
field doesn't change too automatically from tuesday 01/31/06 to monday
01/30/06 but it remains tuesday 01/31/06 and consequently the "Test" task
duration field doesn't change simultaneously and automatically from 2 days
to
1 day but it remains 2 days and what changes is only the "John" assignment
duration that becomes 1 day.
If you than go on th Gant chart you can now see that in the "Test" task
there is a split that goes from the end of 01/30/06 to the end of
01/31/06.
First of all, i'd like to know if you , Steve, and other guys/gals can
experiment the same behvaiour repeating my example and, if the answer is
yes,
i really would like to know what is, in your opinion, the most desiderable
behaviour between the two described above.
The point, i think, is in how, in the case of a fixed duration task,
Microsoft Project applies the basic scheduling formula Duration =
Work/Units.
What i mean is that, while i have no problems in determining which are the
variables of the above formula in a fixed units or fixed work task because
both units and work are pure assignments editable parameters and in these
two
cases the duration variable is always equal to the assignment/s
duration(because when you have at least one assignment the formula applies
to
the assignment/s and not to the task) , i am absoultely not sure about how
i
can determine the three variables in a fixed duration task, or , better, i
really wish to know how Project handle the three variables in a fixed
duration task with at least one assignment.
Really thank you Steve for your and others reply.
Best regards
Michele






If i uncheck all the relative fields, the duration of a fixed duration
task
doesn't change.
On the opposite if i leave all the above fields checked and, for example,
i
change the work for a specific assignment(let's put i have only one
assignment but the same happens also for multiple resources assignments),
if
i select the triangle indicator and click the default selected option and
then i change the finish date of the assignment(decreasing it) then the
duration of the task decreases the same.
If, instead, i do not select the triangle indicator and than i change the
finish date of the assignment(decreasing it) then the duration of the task
doesn't change

"Steve House [Project MVP]" ha scritto:
What version of Project are you using? Can you post EXACTLY what you are
changing and where you are changing it? You mention in this post that
when
you change the work, then change the finish date of the assignment
(assignment finish and task finish are different concepts, by the way)
you
get a triangle indicator. When I do it in Project 2003 Pro I don't get
an
indicator at all. You also reference a "show indicators" in the option
button section of the Project general options. Again, where are you
talking
about? In my Project 2003 Pro desktop, the Tools menu, Options
selection,
General tab doesn't make any reference to "show indicators."

There are several rthings to remember to help you understand what's going
on. First is just what "fixed duration" means. It does NOT mean the
duration can never change under any circumstance. Remember the "prime
directive" is W=D*U and this mathematical identity will never, ever, be
violated no matter what. Any linear equation is of the general formula
Y=mX*b where X is the independent variable, Y is the dependent, and m and
b
are constants. In Project, b=zero so the equation becomes Y=mX. When a
task is designated "fixed xxx" it serves to designate which item in the
work
equation, Work, Duration, or Units is to be treated as the constant,
allowing you to arbitrarily choose which of the other two terms will be
changed (becoming the X) and thus defining which term is to be
calculated.
"Fixed duration" means that when changing Work, Units are recalculated
and
when changing Units, Work is recalculated. If you have the task as
"fixed
duration" and manually force a change to duration, Project reverts to
"fixed units" behaviour and recalculates the Work value.

Second, remember that duration is defined as the number of working time
units AS DEFINED IN THE CALENDAR THAT GOVERNS THE TASK that occur between
when work is first performed and when it is finished. If you change the
finish date without changing the start date, the duration must change by
definition since the difference between start date and finish date in
working time units IS the duration. If a resource hasn't been assigned
to
the task, the calendar that defines which minutes out of the day count
for
duration is the Project calendar. When a resource is assigned, the
calendar
that determines which minutes count is the resource calendar. When a
task
is split, the minutes inside the split are removed from consideration So
a
task that goes one week, stands down for a week, and then resumes for
another week has a 2 week duration, not 3. However, consider two
resources
being assigned with each doing 1 week work. The first works for a week
and
then goes away. A week passes with no activity. Then the 2nd resource
come
in and works a week and the task is finished. In this task the duration
is
3 weeks, not two. Resource "A"s calendar governs the first week, the
Project Calendar governs the 2nd, and Resource "B"'s governs the 3rd.

You mention in another post that you are trying to automate data entry
with
VBA. Why are you trying to automate this in the first place? Setting of
durations and units should be a decision made by the user, not the
software.
Project should not attempt to automate decisions more properly made by
the
managers responsible for the successful completion of the project nor
should
estimating the fundamental project parameters of duration, work, and
units
be something left to mechanical inputs by data entry clerks. Project is
an
aid in the decision making process best used by decision makers, not
simply
a tool to document projects passively.
 
D

davegb

Michele said:
My problem is not about how i can obtain a certain result, my aim is to deep
understand the whole behaviour of Ms Project so that i can automate as much
as it is possible, through vba, the data entry side and the maintaining side
of a project.

If you're successful, please publish your conclusions here. I'd be very
interested in knowing all the possible combinations of assigning and
changing resources in Project and the predictable result. In all the
years (15) I've worked with Project, as a trainer and consultant, I've
never seen this anywhere nor have I met anyone, including the best
experts I know of (that would be some of the regular contributors to
this forum) who claim to know this. There are just too many parameters.
And we're talking permutations here, because how Project responds to a
given series of inputs is very much order dependent, as you've probably
discovered.
With my clients, I start by getting them to minimize the number of
people making direct inputs to Project. I want only specialists who
know how to use it. This is not simple software, and is a serious
problem for "periodic" users, like most Project Managers because if
their projects are large enough such that they only manage one at at
time, they only create a new schedule once every few months or even
years. By the time they're creating one again, they've forgotten most
of what they knew about Project months or years ago. Once you have only
knowledgeable people using it, things get better.
Then, I help them create standard protocols for normal procedures, such
as assigning/changing/deleting resources on tasks and others. It
becomes a requirement to follow those protocols to use Project. This is
the only way I've found to avoid all kinds of problems of doing things
in many different ways and getting many different results.
It sounds as though you're trying to completely automate the scheduling
process, and as others have said, it's simply not possible. It's way
beyond creating a few, or more, algorithms and programming them to meet
any given situation. It's much more complex than that. It's certainly
beyond what can be done with computer technology at the present. Maybe
in 10 or 20 years. In fact, some of the major flaws in Project, like
the Autolink Tasks "feature" [sic] are there because MS developers
tried to make it simpler than it is. It just doesn't reduce down to a
few equations, though as others have pointed out, some simple equations
are involved (like W=DxU).
You understand that i can't spend many hours(Hope not so many..) of
programming and ,once done, realize that i need to rewrite the code because i
didn't predict a Ms project behaviour in some specific circumstance.
Anyway, about what you say regarding calendar i totally agree with you but
it is different from the case i described in my first question.

I think you're stating here exactly what will happen if you try to code
the scheduling process.
I hope this helps in your world.
 

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