Fixed Work implies that the amount of hours (Work or Effort) to complete a
task is constant no matter how many days or resources it is stretched over.
Either Duration or Units can change.
Ex: THe drywall contractor estimates 16 hours to install drywall. This
could be 1 guy 2 days, or 2 guys 1 day or 1 lazy guy working 4 horus for 4
days. The reousrces (Units) and Duration change, but itt is still 16 hours of
Work.
Fixed Units implies that # of resources ( or % thereof) is constant no
matter whether the amount of Work changes or the duration of time to complete
the task changes. Either Duration or Work can change.
Ex: The drywall contractor has only two resources with one set of tools.
Does not matter what might cause work delays (lengthens duration), they don't
have resources to to add that could help finish the job any faster.
Fixed Duration means that the time to complete the task is constant no
matter how many reousrces are assigned or how much work is required. Either
Units or Work can change.
Ex: Drywall compound (mud) takes a fixed amount of time to dry. (Assume
environmental constants here) You can add resources , or have them work more
hours, but the driyng time will not change.
