Defining a taks with fixed start and finish

[Lila]

Hello all,

I am new to MS project and I am using project 2007. I am trying to
define tasks that have fixed start and finish dates as well as a fix
number of days that it would take to complete them. I like porject to
take these inputs and utilize my resource unit percentages so that the
work would span from the start to finish date. Is this at all possible?

 

[Steve House]

If you already know the start date, finish date, duration, and resource
assignment percentages what do you actually expect Project to do for you?
According to your post you already know all of the information Project could
provide. Please note, Project is intended to calculate the schedule for
you - tell you the start and finish dates that you should be scheduling for
your tasks - based the Project kick-off, the necessary dependency
relationships between the tasks, the amount of work or time each is expected
to require, and the availability of the resources to do them. It's not
intended to merely document a schedule you have already devised on your own.
There really is no way to simultaneously input a fixed task start AND a
fixed task finish AND a fixed duration without the possibility that Project
will recalculate one or more of those parameters. Yes, you can sort-of
enter some of those, like entering a Must Start On constraint date and a
specific duration, and set the task to fixed duration but even in that case
the task finish cannot itself be entered as well and there are many
circumstances where Project might
still recalculate something for you.

No offense, but Project is not a piece of software that is readily learned
on your own. It is deceptively simple to use but subtly complex to use
correctly. I'd strongly suggest you seek out and enroll in a decent
training class providing at least a 2-day introduction.

 

[Lila]

Hello,

Thanks for taking the time to reply to my post.

I don't know the resource assignment percentages and I am acutall
hoping that project can calculate that for me based on start and finis
dates and the work effort required. Any thoughts anyone?

As far as training goes, I am taking the PMP road map that needs an M
project course that I will be taking in a few months. Until then I a
hoping that I can figure a few things out on my own..

 

[Lila]

Just to elaborate:

I know that my task starts on day X and has to finish on day Y. I also
know that it takes Z hours to accomplish the task. I like to find out
at what percentage a unit has to work on this task evey day to
accomplish this task between X and Y. Can project do this for me? and
how?

 

[DavidC]

Hi,

Presumably z hours is less than the duration between day x and day y, hence
your desire to identify what that represents as a percentage of the time
duration. The percentage allocation of resources is a reflection of the work
needed to complete the task. So a resource working 100% for eight hours
expends eight hours of work. If the resource works for 50% of the time in
the eight hours, then they only expend four hours work. Working the other
way then, is to calculate the percentage of time the resource needs to spend
to expend z hours of work of (Day y - day x) days of duration, of course
converting the number of days to hours.

So the way to schedule thsi would be to put the duration in to reflect the
number of days between Day X and Day Y, that will then show the task as being
worked on from Day X to Day Y, then in the resources simply add the
percentage of the reosource needed to accomplish the task in that time frame,
based on the earlier calculation. This is not a calculation that Project is
designed to carry out, after all it is generally only the people involved who
know what work is required to complete a task.

One word of caution though. If Day Y is when the task must be finished by,
then you are going down the path of using up any potential float by not
getting the task done as soon as possible. If the resource is ill, or does
no fulfill the work requirement during the task period, it may become
difficult if not impossible to catch up that lost time. A general rule is to
use all the float at the end of a task, not the beginning.

Hope this helps a little, by expanding a little on the response from Steve.

Regards

DavidC

 

[Steve House]

The fact that the task is able to start on day X and has to finish by day Y
does not give you the task duration. A task that is able to begin today and
must be finished by 2 weeks from today does not make it a two week duration
task. If the task requires one man-hour of actual effort and the nature of
the work is such that it requires the resource's full attention whenever he
does it - let's say it's driving a truck 50 miles, that certainly requires
full attention - that task is a 1 hour duration task with a deadline that is
two weeks away. Trying to schedule a project by "completion windows" (for
want ot a better term) is an invitation for disaster. Instead of trying to
figure out the workloading that will take the maximum possible time to do
each task, try scheduling based on the minimum amount of time you can get it
done in, given the maximum effort the resources are able to give to the
task. If Joe can work 100%, that's what you should schedule him at so the
task you're putting him on gets completed as quickly as possible, as far
ahead of its deadline as you can manage so if something gets screwed up (and
the one thing you can count on is something is ALWAYS going to get screwed
up) you've got some wiggle room to still get finished on time.

If you really want to approach it the way you propose, you can set the task
to the desired duration and make it a fixed duration task. Split the screen
and assign the resource in the bottom window entering the estimated work
alongside his name. Clicking OK will result in the resource percentage
being set to whatever units will accomplish the designated work in the
designated time. But note, you CANNOT directly set the start date and the
finish date. Attmepting to do so will result in either a Start No Earlier
Than or a Finish No Earlier Than constraint being set, the one you get
depending on the order that you typed the dates. You can set a duration and
you can even fix either the start or end date with a constraint but you
simply cannot explicitly enter a start, finish, and duration independently
of each other - it just don't work that way. Finish is always going to be
the start date plus the duration, or if you prefer, duration is always the
number of working time minutes between the start and the finish ... that is
engraved in granite as firmly as 2+2=4.

Do keep in mind, however, the start and finish dates are generally NOT a
user input into Project. You don't tell it the schedule you want -- it
tells you the schedule you can get, given what you need to do and the assets
you have on hand with which to get it done.