Setting duration of tasks as percentage of project duration?

[chris togeretz]

Good day! I'm hoping that you can help me figure something out - half
an hour googling and in my "MS Project for Dummies" book doesn't give
me even a hint!

Let's say we have this project:

1. Project
1.1 Task 1 (2 days)
1.2 Task 2 (3 days)

and if Task 2 must be completed after Task 1 is done (FS link) then
the project has a duration of 5 days.

Now. Say you want to squeeze this project into 3 days. Task 1 then is
"allowed" to take only 2*(3/5) = 1.2 days, and Task 2 is allowed to
take 3*(3/5) = 1.8 days.

Is there a way I can specify "work units" (e.g. "2" for Task 1 and "3"
for Task 2) so that I can set their "allowable" durations simply by
changing the overall project length?

Thanks for your help!
Chris

 

[Rod Gill]

No.

For almost every project this would be disastrous! You can enter work for
each task and your MS Project for Dummies book should explain this. Then you
can set the task type to fixed work and reduce teh duration for each task to
what you want. Project will now calculate the Units required to get that
much work done in the duration entered. You now need to demand that many
hours per week (View, Resource usage to see that). If management can't give
you that much then you are very unlikely to achieve the date.

Good luck!

--

Rod Gill
Microsoft MVP for Project

Author of the only book on Project VBA, see:
http://www.projectvbabook.com

Good day! I'm hoping that you can help me figure something out - half
an hour googling and in my "MS Project for Dummies" book doesn't give
me even a hint!

Let's say we have this project:

1. Project
1.1 Task 1 (2 days)
1.2 Task 2 (3 days)

and if Task 2 must be completed after Task 1 is done (FS link) then
the project has a duration of 5 days.

Now. Say you want to squeeze this project into 3 days. Task 1 then is
"allowed" to take only 2*(3/5) = 1.2 days, and Task 2 is allowed to
take 3*(3/5) = 1.8 days.

Is there a way I can specify "work units" (e.g. "2" for Task 1 and "3"
for Task 2) so that I can set their "allowable" durations simply by
changing the overall project length?

Thanks for your help!
Chris

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[chris togeretz]

Thanks for your response, Rod. Your solution to increase resources
would work well, if I had more resources

The reason that I'm trying to be able to "squeeze" tasks into the
total project duration as percentages is the fact that we're often on
very tight timelines and need to know how much time we actually have
to complete small tasks. On projects that have sufficient timing, we
have time enough to perform each task, and to do a good job.

On rushed projects we have to choose which tasks we have to skip
(although this is outside the scope of this conversation) or at the
very least say "... ok .. instead of three hours to put together this
letter I know have two hours...". Yes, we could state at the start
that the task actually takes two hours; but that's just to do a
marginally acceptable job, and isn't what we want to show as the
task's duration. Should I split up tasks into two tasks? e.g. "Write
letter - 2 hours (pressured for time)" and "Write letter - 1 hour
(normally used)" and then when we're short for time reduce the
scheduled time for task 2? It seems to be so over-the-top.


Does that make sense?

 

[Rod Gill]

The other problem with your approach is that half way thru or later you will
realize that you are behind and all remaining tasks will have to be
"clipped", removed or done quick and dirty. This usually means tasks that
earlier in the piece could have been removed with little consequence are
done well and vital tasks at the end get very poor quality.

If all you want is a pretty picture then do whatever paints it. What Trevor
and I are saying is that Project is a tool to help you work out in advance
either what resources you need to get the job done well enough, or what has
to be cut out in advance.

I'm afraid your technique smacks of Google scheduling ("I'm feeling lucky!")

--

Rod Gill
Microsoft MVP for Project

Author of the only book on Project VBA, see:
http://www.projectvbabook.com

Chris, if you persist with this line of "logic" you will get nowhere,
except perhaps a lot more confused.
You will spend time anbd energy trying to rationalise and justify your
approach, when it would be so much easier, faster and more productive to
simply work with the tool rather than against it.
Project planning is about modeling the tasks, durations and predecessors,
and letting the software calculate when the project can finish, not
starting with the answer and working backwards.
We say, IF such and such is the scenario, then this is the result.
If you don't like the result, change what's causing it.
You have to have a clear idea about the distinction between cause and
effect, input and output.
MSP (or any other planning tool) will not do the planning and thinking for
you.

If you have a bunch of tasks and durations which cause the project finish
date to be later than you would like, you must trim some amount of
duration from some or all of the (critical) tasks, but there is no way
that the software can know, or even suggest, how much duration can or
should be trimmed off which tasks. That is a job for a human being who
knows what the project is and what the tasks are.
--
Trevor Rabey
0407213955
61 8 92727485
PERFECT PROJECT PLANNING
www.perfectproject.com.au





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signature database 4597 (20091111) __________

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[Steve House]

Tasks are physical acitviites and as such can only be "squoze" so much. A
painter might be able to apply a maximum of 10 square feet per hour because
that is the flow rate of his painting equipment. He has 400 square feet of
wall to paint. That task will take AT LEAST 40 hours to complete and no
matter how much you would, or even need, it to be done faster it simply
can't be done. Physics and human endurance always trumps management
desires.

 

[chris togeretz]

I thank all of the responders for their excellent work!

Equipped with this feedback, I am much more comfortable going back to
my boss with the right questions:
1) What are the tasks and how are they linked?
2) How long do the tasks take?

And then letting MS Project kick out the schedule. If you don't like
the end date, manually modify the critical path.

Thanks!
Chris

 

[Steve House]

Exactly ... as in my painting example, if you need it done in a shorter
period of time you either a) find a second painter to shoulder some of the
load; or b) buy new equipment that can apply paint at a faster rate without
compromising quality. It's sometimes difficult to resist arbitrarily
assigning numbers based on what will fit the delivery requirements.
Contrary to some manager's beliefs, getting the work done in the time
required is not just a matter of the application of will-power. In the end,
you can't fool mother nature