effort driven and resource driven

Faisal,
for MSP, resource driven means: Task Duration = Work / Units (one resource per task)
effort driven: Task Duration = Total resources work / Total resources Units (several resources per task)
to drive tasks by the effort, allocate a 1st resource and give her the desired amount of work for the task; then allocate additional resources; the more resources you will have on a same task, the shorter the task will be for the same total amount of work
Alexandre

Alexandre,

Interesting answer, I never really considered that a task should be resource driven in such a way, but on reflection if you interpret it literally, i.e. unit availability, I suppose it could.

Using MS Project, I have always understood resource driven to mean that the duration of a task is determined by the assignments resource calendars.

As an example:

Tom only works Mon & Tue
Dick only works Wed & Thu
Harry only works Fri

This means if each resource is assigned to work 1 day on a task, the minimum duration would have to be 5d. (Unless you split it of course)

Regards,

Darren

Darren,
a) you’re right: I just checked what you said in MSP 2003 and MSP2007, and the result is amazing:
whatever setting you give the task, its duration is 5 day;
unless you give the task a calendar and check the next option saying it will not respect the resources calendar: then the task duration is only 2 days, and MSP does not show the Dick and Harry overallocated!
that means the Effort driven only works when the resources are available at the same time, that makes sense
the problem is: MSP does not show the resource being overallocated
b) MSP’s definition for Effort driven as follows: allocate a 1st resource to the task and give it some work, the allocate additional resources to share this amount of work; that’s the same as "Fixed work", but between difefrenbt resources
Alexandre