Negative maximum units

[Sandie K]

One of my colleagues has a MS Project 2007 schedule showing "-100%" in the
max units column for certain resources on the resource sheet. The common
thread among these resources is that the project manager entered varying max
units for each month in their resource calendars, based on assumptions of
what tasks would be occurring when. Two questions:
1) How does project arrive at the max units when the percentages vary by
month and what would cause negative percentages?
2) The varying max units entered in the resource calendars were entered
before estimating the tasks or making assignments. Isn't that problematic?

Thanks in advance,

 

[Jan De Messemaeker]

Hi,

I've never seen negative MAX units and when I try to enter them I get an
error message
BTW when you say Resource Calendars do you mean Resource Availability?
Resource Calendars don't show max units.
But yes, of course you set the availability of a resource before deciding on
the assignments!

--
Jan De Messemaeker
Microsoft Project Most Valuable Professional
+32 495 300 620
For availability check:
http://users.online.be/prom-ade/Calendar.pdf

 

[Sandie K]

A couple of clarifications:
1) She did not enter the negative units; they just appeared that way;
2) I meant to say that she set varying "availability" (not max units--sorry)
in the resource calendars.

An additional question:
How could she know the resource's availability before which tasks would be
occurring during those time periods? I guess it is a "which came first, the
chicken or the egg" question.

 

[Steve House [MVP]]

....snip.

An additional question:
How could she know the resource's availability before which tasks would be
occurring during those time periods? I guess it is a "which came first,
the
chicken or the egg" question.

The resource works an 8 hour day and is able to work on project related
tasks full-time. He has a 100% availability. Or the resource works an 8
hour day but has other things on her plate which will take her away from any
project tasks she's on for on average half of each workday. Her
availability is 50%. Or we have 5 janitors on staff, all of whome could be
used if we needed them. Their availability is 500%.

Availability is how much you COULD use them. Assignment is how much you DO
use them on a given task. Allocation is how much you are using them on ALL
tasks at any one point in time. Leveling moves tasks so they occur in such
a manner that allocation does not exceed availability.

Tasks aren't usually scheduled and then resources assigned on the basis of
their availability. Instead resources are assigned to tasks based on having
the skills required to do the work amd then the tasks adjust their schedule
to fit in where the resource is available. Resource availability drives
task schedules, not the other way around

 

[Sandie K]

Thanks very much for your detailed explanation, Steve.
We discovered that the negative units was a bug in MS Project.
Regards,
SAndie

 

[Sandie K]

Hello Jan,
Thank you for helping my colleague and me yesterday (you found a bug in MS
Project and debugged the file). Your accompanying explanation and your
suggestion to make everyone 100% and not assign them was also a helpful
alternative to changing their availability every month. Sounds like that is a
feature we should avoid.
Regards,
Sandie