Multiple resource units erroneously affect duration?

[dave sprinkle]

I'm new to Project, so I'll concede this may be user error; however, it
appears that Project 2003 is incorrectly calculating task duration when I
change the units of one of my resources. An example:
1 -- Make a new task. Type is 'Fixed Work'. Assign 'resource 1' with 100%
utilization. Assign duration 100 hours.
2 -- Add 'resource 2' with 100% utilization. As you might expect, Project
recalculates duration to be 50 hours.
3 -- Reduce 'resource 2' utilization to 50%. In this case, Project
calculates duration to be 100 hours. Why? Our resource total is now 150% of
our nominal starting point, and yet Project is calculating 100% of our
nominal duration.
4 -- It gets worse. Reduce 'resource 2' utilization to 1%. In this case,
Project reports duration to be 5000 hours.

It seems Project is using the lowest utilization of the two resources and
applying that utilization to the entire effort. Where is the bug -- in
Project's calculation or in my understanding of Project's algorithm?

Thanks in advance for your assistance.

 

[Mike Glen]

Hi Dave,

Welcome to this Microsoft Project newsgroup

I think you'll get answers in my series on Microsoft Project in the TechTrax
ezine, particularly #10 on multiple resource assignments, at this site:
http://tinyurl.com/2xbhc or this:
http://pubs.logicalexpressions.com/Pub0009/LPMFrame.asp?CMD=ArticleSearch&AUTH=23
(Perhaps you'd care to rate the article before leaving the site,
Thanks.)

FAQs, companion products and other useful Project information can be seen at
this web address: <http://www.mvps.org/project/>

Hope this helps - please let us know how you get on

Mike Glen
MS Project MVP

 

[dave sprinkle]

Thanks for the reply, Mike. I understand the issue now. Project assumes
that each of my 2 resources will complete 50% of the total work. The
project's duration then becomes the length of time required by the slowest
(lowest utilized) resource to complete his/her 50%. Awkward.

Thanks again.

 

[Mike Glen]

You're welcome, Dave

Mike Glen
MS Project MVP
See http://tinyurl.com/2xbhc for Project Tutorials