Re: How Does Project calculate

From: Steve House (sjhouse.remove.this_at_to.send.hotmail.com)
Date: 07/07/04 

Date: Wed, 7 Jul 2004 05:59:14 -0400

There are such things as "discressionary links" which is what you are
describing but IMO they are should be used very sparingly. Take this
example of an alternate approach. I have programmer Jim who needs to work
on several 5 day long tasks A, B, C, and D. Each will require his undivided
attention so he can't work on them concurrently. The preferred sequence for
the first 3 is A-B-C but it is not mandatory that they be done in this
order, they are essentially independent of each other and there's no
mandatory process reason one must be done before the other. All three,
OTOH, must be done before task D - the program rollout perhaps - can be
started. The whole thing kicks off next Monday so that's the Project start
date. My initial project plan would show tasks A, B, and C all starting
next Monday and running concurrently through the week. None of them are
linked to each other, but all three have links FS as predecessors to task D
so D would start the following Monday, giving a total project timeline at
this point in the planning cycle of 2 weeks. Now I assign Jim to all 4
tasks. Because he's assigned 100% of his workday to each of A, B, and C,
he's overallocated to the tune of 300% all next week. Resource levelling
will fix that but first I want to look at the desired sequence the tasks
should be performed if they can't be done all at once and I decide I'd like
A to go first, then B, then C. Of course if they *could* be done together
I'd go that route since the overall planning objective is to finish the
project in the shortest possible time consistent with staying in budget. So
before levelling, I designate A as a high priority task, B somewhat lower,
and C a bit lower still. Now when we level, Project delays work to resolve
the overallocation, pushing out C first, then B. So we end up with a
Project schedule running 4 weeks, in the sequence A-B-C-D *without* any
links between A, B, and C. Now we find another fellow available in the 2nd
week that can do similar work. I substitute him for Jim on task B, C jumps
forward a week with Jim still on it and our schedule immediately revises
showing B & C running concurrently in the 2nd week, and the overall schedule
shortens by one week. 

-- 
Steve House [MVP]
MS Project Trainer/Consultant
Visit http://www.mvps.org/project/faqs.htm for the FAQs
"Deluth" <Deluth@discussions.microsoft.com> wrote in message
news:67BD0ADF-BF58-4691-8721-7C6EF1FD83E3@microsoft.com...
> Steve,
>
> Perhaps I am using Project incorrectly.  I am managing a software team.  I
set precedences for the tasks in order to try to set the sequential order of
tasks to be completed by any given resource - this is how the resource knows
what to tackle next.  There are linkages in there that are strict, by this I
mean that the preceeding tasks absolutely need to complete before the
succeeding tasks can occur.  However, most of the tasks are linked to
determine the sequence of events to occur.  The linkage also allows me to
figure out when the project would complete.  using this method, the resource
can easily move around on the tasks since they're weakly linked.  If the
resource feels that they want to complete the tasks out of order, I just
re-order it the way they need to get it done.  This is almost as if you
would start working on assembling the roof while you wait for more woods to
arrive for the completion of the wall, once you complete the wall, you can
finish up on the roof and assemble the house...  :-)
>
> If you can suggest how I can make sure the resources are utilized
correctly without linking sequential tasks, please let me know.  I am
anxious to learn any new concepts.
>
> Thanks!
>
> "Steve House" wrote:
>
> > Alarm bells are going off here.  You say "a later task is being done
before
> > the earlier task."  That may be the proximate cause of the splits you
are
> > getting but it should not be happening.  Predecessor/successor links
mean
> > there is a real physical reason that the later task cannot, under any
> > circumstances, start until the predecessor has finished (assuming a
> > finish-start link for simplicity).  Putting on the roof is not a
successor
> > to erecting the walls because that's the order we want to do it in.  It
is a
> > successor because the law of gravity doesn't give us the option of
building
> > the roof in midair and stuffing the walls in later <grin>.  If it
possible
> > for that later task to start before the earlier one (and it obviously
is, or
> > else your resources would not have been able to do what they're
reporting to
> > you that they did), you should not have the link there in the first
place.
> > I'd strongly suggest you review the dependencies in your project plan to
> > make sure they are valid, serving the function of making the plan a real
> > engineering model of the physical process of creating the project's
> > deliverables and are not in there to force the plan into some
pre-conceived
> > idea of the way the work "should" progress.
> >
> >
> > -- 
> > Steve House [MVP]
> > MS Project Trainer/Consultant
> > Visit http://www.mvps.org/project/faqs.htm for the FAQs
> >
> >
> >
> > "Deluth" <Deluth@discussions.microsoft.com> wrote in message
> > news:0DA0AC89-EE27-4261-A4EA-80AA0CE6C54A@microsoft.com...
> > > I would like to know when and how Project does its calculations.  My
> > resources sometimes change the order of the tasks they're doing.
Sometimes,
> > a later task starts before the earlier task.  When this occurs, I enter
the
> > percent complete into the later task.  When I open up the project again,
the
> > end date seemed to have been recalculated based on the percent completed
and
> > the remaining duration.  Unfortunately, when I try to repeat this to see
how
> > Project calculates, it doesn't.  As if it only calculates when there's
been
> > some time passed since the last time the project was opened.
> > >
> > > I know that Project calculates when the acutal finish (or 100%
complete)
> > has been entered.  But I am seeing that it sometime calculates on
> > percentages as well.  I would like to know when does it do this and how
does
> > it calculate, as well as, why sometimes and not others...
> > >
> > > Thannks in advance for any help...
> >
> >
> >

Relevant Pages

  • Re: How Does Project calculate
    ... If this Priority/Leveling method is not feasible for such a large implementation, ... > will fix that but first I want to look at the desired sequence the tasks ... I substitute him for Jim on task B, ... > tasks to be completed by any given resource - this is how the resource knows ...
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  • Re: Resource vs. Task Dependency
    ... > resource "dependency" the functions like a task dependency does. ... > sequence is determined by the availability of the required resource and ... > process logic - then leveling coupled with leveling priorities will ...
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  • Re: Resource vs. Task Dependency
    ... but I'm still trying to grasp the advantage of a>> resource "dependency" the functions like a task dependency does. ... >> Obviously they must be sequenced but the kicker in my mind is WHAT> sequence? ... >> You say one would be able to see timelines driven by task dependencies>> versus on driven by resource dependencies but I don't see how it could be>> possible that they are different. ... Critical path scheduling got it's big break from>>> the ...
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  • Re: Predecessors!
    ... > links to sequence them are superfluous and in fact in the scenario I'm ... > task" (yes I could put milestones in as subtasks as well and have one as a ... I assign resource Barney to ... >> Mark Durrenberger, PMP ...
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  • Re: How to assign the same resource to the same task?
    ... Though I don't know your exact situation, most likely these are NOT the same task in fact but rather multiple occurances of similar tasks. ... If your resource is re-visiting these tasks over a number of years it's very likely that each "visit" results in its own unique deliverable and thus is really each reptition is separate independent task with similar work activity to the others. ... If I have to paint the walls of my room, each wall takes 1 day, and I'm going to do one wall a month, it's not one task lasting 4 months, it's 4 different 1-day tasks each involving painting a wall. ... How do I assign the same resource multiple times to the same task? ...
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