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From: Ritesh on 22 May 2008 10:30
Hi

I have a very basic question.

My Project has 8 hours per day. (Hours Per Day Setting)

Resource A works for 9 hours per day and Resource B works for 8 hours
per day.(I Set up the Resource Calendar)

I created a fixed units task (say Task 1) with 65 hours of Work and
assigned both A &B to this task at 50%. Now Project Calculates the
duration for this task as 9 days with work assigned to both A & B as
32.5 hours.

How does Project Arrive at the duration of 9 days, is my question?.

As Work = Duration * Units, going by this logic:

For A => 9 days * 9 hours per day * 50% = 40.5 hours of Work
For B => 9 days * 8 hours per day * 50% = 36 hours of Work
Total = 76.5 hours, where as the work that I entered is 65 hours.

How does Project actually do the calculations?


From: John on 22 May 2008 11:45
In article
<f3804087-52ff-4538-9bae-95be6fab9234(a)27g2000hsf.googlegroups.com>,
Ritesh <riteshjadwani(a)yahoo.com> wrote:

> Hi
>
> I have a very basic question.
>
> My Project has 8 hours per day. (Hours Per Day Setting)
>
> Resource A works for 9 hours per day and Resource B works for 8 hours
> per day.(I Set up the Resource Calendar)
>
> I created a fixed units task (say Task 1) with 65 hours of Work and
> assigned both A &B to this task at 50%. Now Project Calculates the
> duration for this task as 9 days with work assigned to both A & B as
> 32.5 hours.
>
> How does Project Arrive at the duration of 9 days, is my question?.
>
> As Work = Duration * Units, going by this logic:
>
> For A => 9 days * 9 hours per day * 50% = 40.5 hours of Work
> For B => 9 days * 8 hours per day * 50% = 36 hours of Work
> Total = 76.5 hours, where as the work that I entered is 65 hours.
>
> How does Project actually do the calculations?

Ritesh,
Well here's how it all works out.

First, because you are assigning both resources when the task is
initially created, Project will allocate the total task work hours
equally between the two resources (i.e. each resource has 65/2 = 32.5
hrs.)

Next, in the absence of work contouring, Project will linearly spread
each resource's hours with resource A working 4.5 hours per day and
resource B working 4 hours per day. At that rate, resource A works 7
days at 4.5 hours per day which sums up to 31.5 hours. Then on the 8th
day, he only needs to work 1 hour to make up his total of 32.5 hours.
Similarly, resource B works 8 days at 4 hours per day and one half hour
on the 9th day for his total of 32.5 hours.

Third, duration is the difference in working time between the task start
and task finish. In your scenario the easiest way to validate the task
duration is to look at the task Start and Finish fields (include the
time). In my test of your scenario, the task start is 5/22/08 at 8:00 am
and the task finish is 6/3/08 9:00 am. The working time difference is 72
hours and given a setting of 8 hrs/day for duration calculations, that
is 9 days exactly.

Probably the best way to see the above is via the Task Usage view, with
the timescale set to show days and hours.

Hope this helps.
John
Project MVP
From: Jim Aksel on 22 May 2008 11:56
switch to the task usage view to see how the hours are spread. What I see is
the program is honoring the 50% units (4.5hr/day for A, 4 hours/day for B)
up until the last two days.
On the last two days, Resouce A works 1 hour on day 8 and no hours on day 9.
Resource B works 4 hours on day 8 (per 50% allocation) and then 0.5 hours
day 9.

It appears reasonable the program should be working resource A 1.5 hours on
day 8 instead of 1 hour. This would let the task complete in 8 days and
certainly does not violate any availability issues for resource A.

Perhaps someone else will post who has more in depth knowledge of the
assignment algorithm. My SWAG tells me it takes the 65 hours and divides it
equally amongst the number of resources present, then runs out those hours
based on the assignment units (50%) which determines the number of days that
resource will need to run.

I did an experiment with 60 hours and three resources. Sure enough,
everyone gets 20 hours. So it appears the first thing project does is divide
the work equally among the resources present, then uses Units% and that
fractional portion of the work to determine the duration of a resource
assignment.

--
If this post was helpful, please consider rating it.

Jim

Visit http://project.mvps.org/ for FAQs and more information
about Microsoft Project



"Ritesh" wrote:

> Hi
>
> I have a very basic question.
>
> My Project has 8 hours per day. (Hours Per Day Setting)
>
> Resource A works for 9 hours per day and Resource B works for 8 hours
> per day.(I Set up the Resource Calendar)
>
> I created a fixed units task (say Task 1) with 65 hours of Work and
> assigned both A &B to this task at 50%. Now Project Calculates the
> duration for this task as 9 days with work assigned to both A & B as
> 32.5 hours.
>
> How does Project Arrive at the duration of 9 days, is my question?.
>
> As Work = Duration * Units, going by this logic:
>
> For A => 9 days * 9 hours per day * 50% = 40.5 hours of Work
> For B => 9 days * 8 hours per day * 50% = 36 hours of Work
> Total = 76.5 hours, where as the work that I entered is 65 hours.
>
> How does Project actually do the calculations?
>
>
>
From: Ritesh on 23 May 2008 03:00
On May 22, 8:45 pm, John <mjen...(a)theriver.com> wrote:
> In article
> <f3804087-52ff-4538-9bae-95be6fab9...(a)27g2000hsf.googlegroups.com>,
>
>
>
>
>
>  Ritesh <riteshjadw...(a)yahoo.com> wrote:
> > Hi
>
> > I have a very basic question.
>
> > My Project has 8 hours per day. (Hours Per Day Setting)
>
> > Resource A works for 9 hours per day and Resource B works for 8 hours
> > per day.(I Set up the Resource Calendar)
>
> > I created a fixed units task (say Task 1) with  65 hours of Work and
> > assigned both A &B to this task at 50%.  Now Project Calculates the
> > duration for this task as 9 days with work assigned to both A & B as
> > 32.5 hours.
>
> > How does Project Arrive at the duration of 9 days, is my question?.
>
> > As Work = Duration * Units, going by this logic:
>
> > For A =>    9 days * 9 hours per day * 50%  = 40.5 hours of Work
> > For B =>    9 days * 8 hours per day * 50% = 36 hours of Work
> > Total = 76.5 hours, where as the work that I entered is 65 hours.
>
> > How does Project actually do the calculations?
>
> Ritesh,
> Well here's how it all works out.
>
> First, because you are assigning both resources when the task is
> initially created, Project will allocate the total task work hours
> equally between the two resources (i.e. each resource has 65/2 = 32.5
> hrs.)
>
> Next, in the absence of work contouring, Project will linearly spread
> each resource's hours with resource A working 4.5 hours per day and
> resource B working 4 hours per day. At that rate, resource A works 7
> days at 4.5 hours per day which sums up to 31.5 hours. Then on the 8th
> day, he only needs to work 1 hour to make up his total of 32.5 hours.
> Similarly, resource B works 8 days at 4 hours per day and one half hour
> on the 9th day for his total of 32.5 hours.
>
> Third, duration is the difference in working time between the task start
> and task finish. In your scenario the easiest way to validate the task
> duration is to look at the task Start and Finish fields (include the
> time). In my test of your scenario, the task start is 5/22/08 at 8:00 am
> and the task finish is 6/3/08 9:00 am. The working time difference is 72
> hours and given a setting of 8 hrs/day for duration calculations, that
> is 9 days exactly.
>
> Probably the best way to see the above is via the Task Usage view, with
> the timescale set to show days and hours.
>
> Hope this helps.
> John
> Project MVP- Hide quoted text -
>
> - Show quoted text -

Thanks John. Your reply certainly helps. However, how can we validate
the formula Duration = Work/Units. I am unable to figure out how in
this case, the Duration of 9 days (or 72 hours) equals the Work(65
hours) dividied by Units (50%).
From: Markarina on 23 May 2008 04:59
On May 23, 8:00 am, Ritesh <riteshjadw...(a)yahoo.com> wrote:
> On May 22, 8:45 pm, John <mjen...(a)theriver.com> wrote:
>
>
>
> > In article
> > <f3804087-52ff-4538-9bae-95be6fab9...(a)27g2000hsf.googlegroups.com>,
>
> > Ritesh <riteshjadw...(a)yahoo.com> wrote:
> > > Hi
>
> > > I have a very basic question.
>
> > > My Project has 8 hours per day. (Hours Per Day Setting)
>
> > > Resource A works for 9 hours per day and Resource B works for 8 hours
> > > per day.(I Set up the Resource Calendar)
>
> > > I created a fixed units task (say Task 1) with 65 hours of Work and
> > > assigned both A &B to this task at 50%. Now Project Calculates the
> > > duration for this task as 9 days with work assigned to both A & B as
> > > 32.5 hours.
>
> > > How does Project Arrive at the duration of 9 days, is my question?.
>
> > > As Work = Duration * Units, going by this logic:
>
> > > For A => 9 days * 9 hours per day * 50% = 40.5 hours of Work
> > > For B => 9 days * 8 hours per day * 50% = 36 hours of Work
> > > Total = 76.5 hours, where as the work that I entered is 65 hours.
>
> > > How does Project actually do the calculations?
>
> > Ritesh,
> > Well here's how it all works out.
>
> > First, because you are assigning both resources when the task is
> > initially created, Project will allocate the total task work hours
> > equally between the two resources (i.e. each resource has 65/2 = 32.5
> > hrs.)
>
> > Next, in the absence of work contouring, Project will linearly spread
> > each resource's hours with resource A working 4.5 hours per day and
> > resource B working 4 hours per day. At that rate, resource A works 7
> > days at 4.5 hours per day which sums up to 31.5 hours. Then on the 8th
> > day, he only needs to work 1 hour to make up his total of 32.5 hours.
> > Similarly, resource B works 8 days at 4 hours per day and one half hour
> > on the 9th day for his total of 32.5 hours.
>
> > Third, duration is the difference in working time between the task start
> > and task finish. In your scenario the easiest way to validate the task
> > duration is to look at the task Start and Finish fields (include the
> > time). In my test of your scenario, the task start is 5/22/08 at 8:00 am
> > and the task finish is 6/3/08 9:00 am. The working time difference is 72
> > hours and given a setting of 8 hrs/day for duration calculations, that
> > is 9 days exactly.
>
> > Probably the best way to see the above is via the Task Usage view, with
> > the timescale set to show days and hours.
>
> > Hope this helps.
> > John
> > Project MVP- Hide quoted text -
>
> > - Show quoted text -
>
> Thanks John. Your reply certainly helps. However, how can we validate
> the formula Duration = Work/Units. I am unable to figure out how in
> this case, the Duration of 9 days (or 72 hours) equals the Work(65
> hours) dividied by Units (50%).

I'm not pretending to be an expert here, but the way I understand it
is that when you set units to 50% you restrict the number of hours a
resource can work in one day not how the effort is split, so in this
case when you have two resources as has been previously said by
default project splits the effort equally so each resource has 32.5
hours of work. Given that you have set units to 50% this means your
8hr/day resource can work only 4 hours/day and as such the duration
will be calculated as 32.5/4 = 8.125 days which in this case means
project will report the duration as 9days.
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