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.