Allocating multiple resources to a task does not shorten the durat

[Frank]

Hi,

This problem is happening with several tasks on my plan.

When I try and allocate more people to a activity, it starts to decrease the
duration (the task type is default, effort driven). But it gets to a point
where by allocating a resouce, it reduces the duration by just a day whilst
reducing the work of the other resources. I need to throw people at the
activity to reduce the duration and meet a deadline. But throwing more people
at it is not helping.

Any ideas

Frank

 

[Jim Aksel]

Frank - There is a point of diminishing return. First, set your activity to
fixed work. Then, adding more resources will let 9 women have a baby in one
month if each are allocated to 100%.

I think what you may be experiencing is that you have work divided among a
given set of resources, you can only slice the pie so many ways. So, if you
add additional resources at 100%, there is only so much work left over for
the other participants which will decrease their allocated percentage. The
key here is "Fixed Work"

 

[davegb]

Hi,

This problem is happening with several tasks on my plan.

When I try and allocate more people to a activity, it starts to decrease the
duration (the task type is default, effort driven). But it gets to a point
where by allocating a resouce, it reduces the duration by just a day whilst
reducing the work of the other resources. I need to throw people at the
activity to reduce the duration and meet a deadline. But throwing more people
at it is not helping.

Any ideas

Frank

Well, Frank, you're getting an excellent lesson in reality. The first
person you add to an effort driven tasks decreased the duration by 50%.
The second by 33%. The third by 25%, the fourth by 20%, etc. Do you see
a trend here? It's called the "Law of Diminishing Returns", and I can't
think of a better example. And it doesn't even take into account that
as the number of people on the task increases, the need for EFFECTIVE
supervision and better communication increases. At some point, adding
people will actually slow down the time it takes to do the task. You
could well be at that point already.

I know this may be hard to believe, but it's possible you haven't
scheduled enough time to do this task NO MATTER HOW MANY PEOPLE you
assign to it! Any task has an absolute minimun amout of time it can be
done in, regardless of how many resources you put on it. If it takes
one programmer a month to write a particular program, can 10,000
programmers write the same program in 4.32 minutes (one-tenthousandth
of a month)?

There are other ways to shorten the duration of a task. Without knowing
the specifics, it's hard to make a recommendation. Maybe others here
have some suggestions.

Hope this helps in your world.

 

[JulieS]

Hi Frank,

I'm *guessing* that one of the resources assigned has non-working time
in his/her calendar. If you split your screen (Window > Split) to show
the Task Form and then format the Task Form to show Resource Schedule,
there may be a resource who is finishing their work on the task after
all others. You may also see an uneven distribution of work.

For example: In an effort-driven fixed unit task (the default), if I
assign 1 resource at 100% to a 5 day duration task, Project calculates
40 hours of work. The task starts Monday, ends Friday.

Add another resource, total work stays at 40 hours, each resource is
working 20 hours and the duration modifies to 2.5 days. The task starts
Monday and ends mid-day Wednesday.

As I continue to add resources (all with resource calendars which match
the project calendar), duration continues to drop and the 40 hours of
work is evenly divided among the additional resources.

However, if I throw a resource into the mix who has non-working time in
his/her calendar, the process becomes a bit muddled. If I start again
with one resource whose calendar matches the project calendar, again,
same story -- 40 hours of work, 5 day duration, 100% assignment units.
The task starts Monday and ends Friday.

If I add a resource to the task who only works Monday, Wednesday, and
Friday. The task duration drops to 3.5 days, instead of 2.5 days. The
task starts on Monday and ends Friday mid-day. The first resource (with
the non-modified calendar) starts working Monday morning and finishes
his/her work Wednesday mid-day. But the second resource still has 20
hours of work to accomplish but only on Monday, Wednesday, and Friday.
So his/her work finishes mid-day on Friday. It is that second resource
who is driving the finish date of the task.

If I continue to add additional resources, things get even more
interesting. The original two resources are both scheduled to work
11.77 hours but the newly added resource is scheduled to work 16.47
hours. They all now finish their assignment at different hours of
different days. The duration is still being driven by the resource who
finishes last.

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

Julie

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

 

[Frank]

Hi Frank,

I'm *guessing* that one of the resources assigned has non-working time
in his/her calendar. If you split your screen (Window > Split) to show
the Task Form and then format the Task Form to show Resource Schedule,
there may be a resource who is finishing their work on the task after
all others. You may also see an uneven distribution of work.

For example: In an effort-driven fixed unit task (the default), if I
assign 1 resource at 100% to a 5 day duration task, Project calculates
40 hours of work. The task starts Monday, ends Friday.

Add another resource, total work stays at 40 hours, each resource is
working 20 hours and the duration modifies to 2.5 days. The task starts
Monday and ends mid-day Wednesday.

As I continue to add resources (all with resource calendars which match
the project calendar), duration continues to drop and the 40 hours of
work is evenly divided among the additional resources.

However, if I throw a resource into the mix who has non-working time in
his/her calendar, the process becomes a bit muddled. If I start again
with one resource whose calendar matches the project calendar, again,
same story -- 40 hours of work, 5 day duration, 100% assignment units.
The task starts Monday and ends Friday.

If I add a resource to the task who only works Monday, Wednesday, and
Friday. The task duration drops to 3.5 days, instead of 2.5 days. The
task starts on Monday and ends Friday mid-day. The first resource (with
the non-modified calendar) starts working Monday morning and finishes
his/her work Wednesday mid-day. But the second resource still has 20
hours of work to accomplish but only on Monday, Wednesday, and Friday.
So his/her work finishes mid-day on Friday. It is that second resource
who is driving the finish date of the task.

If I continue to add additional resources, things get even more
interesting. The original two resources are both scheduled to work
11.77 hours but the newly added resource is scheduled to work 16.47
hours. They all now finish their assignment at different hours of
different days. The duration is still being driven by the resource who
finishes last.

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

Julie

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




Thanks everyone for taking the time to reply.

I am going to review and have a look at the suggestions offered.

Frank

 

[JulieS]

I am going to review and have a look at the suggestions offered.

Frank

You're welcome Frank. Let us know how you get along.

Julie

 

[Frank]

You're welcome Frank. Let us know how you get along.

Julie


One of my colleagues suggested going into ‘Task Usage’ and manual editing the resources there. I have done this and found that I can schedule much better. Are there any downsides to this approach?

Thanks

Frank

 

[JulieS]

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

Thanks

Frank

Hi Frank,

No there is not. You may also show the Task Form in the bottom pane
(Window > Split) if you don't need to edit timescaled work (day by day
etc.) but would rather edit the total work for the task.