Trying to understand how the numbers add up in Resource Usage view

[Bobg]

Hello,

I am relatively new to Project and am trying to understand how the numbers
add up in the Resource Usage View. I have read several posts on how resources
can appear overallocated at the day level when it does not seem that they
should be (because they are overallocated at the hour or minute level). To
fully understand, I changed the timescale for the view to be
days/hours/minutes.

My confusion is due to the fact that I see most minutes with work of .02h.
Sometimes they appear as overallocated and sometimes they do not. In
addition, the row that contains the totals per minute for a given resource
never seems to go above .02h, even if there is more than one task below it
assigned .02h for that one minute.

I think I understand that the .02 is approximatley 1/60, but am confused
about why it is sometimes overallocated and sometimes the sheet itself does
not seem to add up.

Thanks for any light that can be shed on this!

Bob

 

[JulieS]

Hello,

I am relatively new to Project and am trying to understand how the
numbers
add up in the Resource Usage View. I have read several posts on how
resources
can appear overallocated at the day level when it does not seem that
they
should be (because they are overallocated at the hour or minute
level). To
fully understand, I changed the timescale for the view to be
days/hours/minutes.

My confusion is due to the fact that I see most minutes with work of
.02h.
Sometimes they appear as overallocated and sometimes they do not. In
addition, the row that contains the totals per minute for a given
resource
never seems to go above .02h, even if there is more than one task
below it
assigned .02h for that one minute.

I think I understand that the .02 is approximatley 1/60, but am
confused
about why it is sometimes overallocated and sometimes the sheet itself
does
not seem to add up.

Thanks for any light that can be shed on this!

Bob

Hello Bob,

Well, I must say, you *are* dedicated to look at a detail view of
minutes

You may find it helpful to temporarily show work in minutes to help with
the conversion from fractional hours.

To shed a bit of light, bear in mind that it is not just how many hours
or minutes a resource is assigned to work, but what the resource's
assignment units to each task are as compared to the resource's maximum
units.

For example, you see .02h of work for a resource on a minute timespan.
If you look at work in minutes, you'll see Project rounds that to 1 min.
In truth, it is probably a fraction of a minute -- Project just "rounds
up." I see the same .02h when assigning a resource at 80% assignment
unit to a task. The resource generates .8 of a minute of effort for
every 1 minute in the task, but Project shows me the work as 1 min. If
I assign the same resource to another task at 20% assignment units and
that task overlaps the first task, the resource is overallocated -- her
total assignment units is 100%, but her maximum units are 80%.
Interestingly enough, the second assignment at 20% shows 0min of work in
the resource usage hourly view -- project just rounds down to 0 from .2.

So the differences you are seeing, particularly when looking at a minute
scale is due to Project rounding values up or down as it does not
display units at less than 1 minute.

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

Julie
Project MVP

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

 

[Bobg]

Hello Bob,

Well, I must say, you *are* dedicated to look at a detail view of
minutes

You may find it helpful to temporarily show work in minutes to help with
the conversion from fractional hours.

To shed a bit of light, bear in mind that it is not just how many hours
or minutes a resource is assigned to work, but what the resource's
assignment units to each task are as compared to the resource's maximum
units.

For example, you see .02h of work for a resource on a minute timespan.
If you look at work in minutes, you'll see Project rounds that to 1 min.
In truth, it is probably a fraction of a minute -- Project just "rounds
up." I see the same .02h when assigning a resource at 80% assignment
unit to a task. The resource generates .8 of a minute of effort for
every 1 minute in the task, but Project shows me the work as 1 min. If
I assign the same resource to another task at 20% assignment units and
that task overlaps the first task, the resource is overallocated -- her
total assignment units is 100%, but her maximum units are 80%.
Interestingly enough, the second assignment at 20% shows 0min of work in
the resource usage hourly view -- project just rounds down to 0 from .2.

So the differences you are seeing, particularly when looking at a minute
scale is due to Project rounding values up or down as it does not
display units at less than 1 minute.

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

Julie
Project MVP

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

Thank you Julie.

I didn't really WANT to look down to the minute level, but just want to
understand where the numbers come from

I understand the rounding idea so I think that explains why sometimes it
shows as overallocated and sometimes not. Do you see the same thing that I do
in the rows that are supposed to show a total per minute for the resource? If
I have two tasks that show as .02h each in a given minute, my total still
shows as .02h also. I am still confused on that one. No matter how it rounds
to get to .02h, when you add two of them together you should get more than
..02h (I think....)

Thank you again for your help!

 

[JulieS]

Thank you Julie.

I didn't really WANT to look down to the minute level, but just want
to
understand where the numbers come from

I understand the rounding idea so I think that explains why sometimes
it
shows as overallocated and sometimes not. Do you see the same thing
that I do
in the rows that are supposed to show a total per minute for the
resource? If
I have two tasks that show as .02h each in a given minute, my total
still
shows as .02h also. I am still confused on that one. No matter how it
rounds
to get to .02h, when you add two of them together you should get more
than
.02h (I think....)

Thank you again for your help!

You're welcome Bob.

To the comment about when does .02h + .02h = .02h -- only in Project.

You can reproduce it fairly easily. I have a resource assigned to 50%
to one task and it shows .02h on a minute by minute basis -- it's
really 30 seconds. Another task the resource is assigned at 80% also
shows as .02h -- it's really 48 seconds. At the resource line, it still
shows .02h -- again Project rounds the total of 78 seconds (1 min 6
seconds) down to the nearest 1 minute. It's even more unusual if you
change the display of work to minutes. I see 1m work for task a, 1m
work for task b and 1 min work at the resource line

When I set the lower tier of the time scale to show 2 minute increments
the total starts to display a bit more correctly but again, only due to
rounding. Task A now correctly show 1 minute of work for the two minute
time span (30 seconds per minute) and Task B shows 2 minutes -- rounding
the 96 seconds up to 2 minutes. Any fraction of a minute below .49
rounds down -- any .50 rounds up.

Julie

 

[Bobg]

You're welcome Bob.

To the comment about when does .02h + .02h = .02h -- only in Project.

You can reproduce it fairly easily. I have a resource assigned to 50%
to one task and it shows .02h on a minute by minute basis -- it's
really 30 seconds. Another task the resource is assigned at 80% also
shows as .02h -- it's really 48 seconds. At the resource line, it still
shows .02h -- again Project rounds the total of 78 seconds (1 min 6
seconds) down to the nearest 1 minute. It's even more unusual if you
change the display of work to minutes. I see 1m work for task a, 1m
work for task b and 1 min work at the resource line

When I set the lower tier of the time scale to show 2 minute increments
the total starts to display a bit more correctly but again, only due to
rounding. Task A now correctly show 1 minute of work for the two minute
time span (30 seconds per minute) and Task B shows 2 minutes -- rounding
the 96 seconds up to 2 minutes. Any fraction of a minute below .49
rounds down -- any .50 rounds up.

Julie

Great explanation. I believe that I understand it now!

 

[JulieS]

Great explanation. I believe that I understand it now!

Great Bob. Now you can set your timescale back to a slightly more "big
picture" zoom

Julie