Do you always put multiple predecessors for milestones?

G

gueb

task 1 (one day)
task 2 (one day) (predecessor is task 1)
milestone (predecessor is task 2)

if task 2 is started and completed before task 1, then task 2 take more time
than expected, the milestone is not updated, still on plan to deliver after 2
days..

- is the only solution is to put multiple predecessors to the milestone
(every preceding task?
- can i add predecessor after the baseline is generated?

http://pages.videotron.com/gueb/images/other/msproject1.JPG
 
S

Steve House

If it is at all possible for task 2 to start and finish before task 1 then
you shouldn't have a predecessor/successor relationship at all (assuming the
standard FS link). The link means that there is a concrete physical reason
that task 1 MUST finish before it will be possible for task 2 to start - or
more precisely, the finish of task 1 controls the allowable start of task 2.
Perhaps task 1 produces a component that is required by task 2. So if it
is even possible for it to happen as you write in your post, you need to
completely rethink your links in the first place.
 
G

gueb

if i was able to plan that, the links would be different.

but the baseline is generated, the project started, and a supplier didn't
give me the good specifications to start task 1, so i ask the ressource to
start task 2 right away.

so how to deal with this situation? things are easy to plan, but the project
is not always running as you plan it :(
 
J

Jim Aksel

Answer is in two parts.
First is Program Management- If there is a concrete reason that Task1 must
complete prior to the Start of Task2 you have NO business doing anything with
Task2. You stop work and go back to Task1 and tell your supplier to provide
the appropriate data. Trust me, the agony you save is your own. You should
leave the linkages the way they are.

Second - more pragmatic. Let's say Task1 is "Final Specs Released" and
Task2 is "Design". Well, you might be able to use the preliminary spec to
get started (Preliminary spec would be the end result of some other step.)

In this case, delete the FS link between 1 & 2. Instead, go to Task3
milestone and make Task1 and Task2 predecessors to Task3. Since you took the
risk of starting task2 prior to conclusion of Task1, then insert the column
[Acutal Start] and key a date in there for Task2.

However, I don't know your real situation with real tasks. So, there really
is another task you have to do. Certainly Task2 cannot complete prior to the
completion of Task1. So, you can add a Finish to Finish (FF) predecessor on
Task2. You can change the predecessor type in the Task Inforamtion Dialog
Box (double click the task, pull the Predecessors tab).

In reality, I suggest you split Task2 into two tasks -- What you can do
before Task1 is complete make that Task2a. Then Task2b is what cannot happen
until Task1 is complete. You can link them logically that way.

Without much more specific information about your specific case, this is the
best I can offer at this time.
--
If this post was helpful, please consider rating it.

Jim

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

gueb

thanks guys.

but if i remove the link between task 1 and 2 (FF or no link), then the 2
task finish on the same day, and my resource need to work 15 hours instead of
7.5 that days.

this is why i need a link. and the link is valid, the problem is something
happen during the project (not during planification) and i need to take an
action.
 
G

gueb

Project seems ok if I dont execute the task in the planified order, at the
end, it will be ok.

The problem is when one of the task executed in the wrong order need more
time to execute, the milestone is not updated. The end date on the
recapitulative task is good, not the milestone.
 
J

Jim Aksel

Check the constraints and task type of the milestone.
Double click on the milestone and examine the predecessors by pulling the
predecessors tab. Make sure they are what you want including the type FS, FF,
etc.

Pull the advanced tab. Look for the task type, such as "Start No Later
Than", "Finish No Earlier Than", etc. You usually want this to be "As Soons
As Possible" unless you have a VERY good reason to make it something else.

If there is a date under "Deadline" consider clearing it, but this usually
will not force your task to a given date.

From that I understand you have this:
1 Task1
2 Task2 pred is Task1 FS
3 Milestone pred is Task1 FS and Task2 FS

Milestone now finishes at the later of Task1 and Task2.
You are choosing to pollute the link between T1 and T2 by using Actual
Dates. In MS Project, anything in the Actual Start or Actual Finish fields
will override the scheduling logic. This is a poor way to do business but it
will work.


--
If this post was helpful, please consider rating it.

Jim

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

Steve House

Sorry, but this is the incorrect use of linking, IMHO. A
predecessor/successor link means there's a physical relationship between the
two tasks - ie, you have to erect walls before you install a roof because
Mother Nature's force of gravity doesn't allow you to build the roof
unsupported in midair and then come back later to stuff the walls in
underneath it. What you are describing is sequencing required by a resource
allocation issue - task 1 and task 2 are both to be done by the same
resource, he can't do both at once so the two tasks must be sequenced one
after the other. This sort of sequencing is NOT the function of dependency
links. For this you use resource leveling to introduce the delay for task 2
into the schedule. For example, both tasks are 1 day duration and the
project starts Monday. Initially tasks 1 and 2 will be scheduled to run at
the same time, both on Monday. Assign resource Joe 100% to each. They're
still both on Monday but Joe is overallocated. Run Resource Leveling. Task
2 will move to Tueday WITHOUT the need for spurious links to drive it there.
IF you need to extert manual control over the preferred order the task are
done, use the Task Priority settings to indicate which should be done first
and which should be done second.

The way I suggest, if you were to find someone else that could take over one
of the tasks you really could get both of them done at once and get your
project done all the sooner. The way you're doing it, even if you find
another resource to take over one of the tasks it doesn't save you any time
overall. AND, the way I suggest all your problems with the disparity
between plan and actual goes away.

HTH
 
G

gueb

this seems exactly what im looking for for this special situation... where do
i find the resource leveling menu

thanks!!!!!!!!!!!!
 
S

Steve House

Tools menu, Resource Leveling. Task priority settings are found on the Task
Information screen with bigger numbers indicating higher priorities.
 
G

gueb

Jim Aksel proposed to use 2 predecessors for my milestone, seems perfect for
me.
Steve House proposed removing predecessors and use resource leveling
Trevor Rabey give good arguments not to use resource leveling

@Trevor

You said "But the situation calls for a clean new plan to reflect the
changed intentions asap rather than clinging to the old plan."

Is it a common way to redo a new plan everytime a situation happen?

HOW WILL YOU PLAN THIS PROJECT (to help me understand)

A handyman do a project for you. 4 task of 5 days.

- painting
- triming
- fixture
- floor

I use predecessor to see a 4 weeks jobs, done by 1 man. Everything is good,
but the fixture is broken, and will be repaired in 2 days. I cannot stop the
job, so the handyman will start the floor. Should i redo the plan?

It is similar to my original problem, if the fixture job is longer, than the
milestone will not reflect the problem
 
S

Steve House

What are the obligatory physical dependencies in your scenario? I'm
assuming trimming refers to fine detail work in painting such as baseboards
and the like. If so, painting would be a predecessory of trimming. But is
the fixture attached to a painted wall? If so, you probably need to paint
the wall before attaching the fixture. But if it's not attached, then you
might not. Can the floor be done without the fixture in place, does it have
to be done before the fixture is installed (floor standing fixture) or can
it be done at anytime (fixture on the wall)?

In other words, don't use links to set the schedule into what you think it
'ought' to be. Use links to describe the physical process that MUST be
followed and discover what schedule it allows you.
 
G

gueb

All 4 tasks can be done in any order. So what are the good planning options,
without using resource leveling and not overallocating ressources?
 
S

Steve House

If you don't use resource levelling links are the only way to establish the
sequencing (well, you could use SNET constraints but that opens up an even
bigger can of worms). But why are you opposed to levelling? In your sample
scenario it is the ideal solution, a perfectly normal practice, and only
involves a few mouse clicks. I'd have "Start" as a milestone and link it as
a predecessor to all 4 tasks. Since there is no obligatory sequence none of
the tasks would be linked to each other. If there is a preferred sequence,
descending Task Priorities would be assigned with the highest priority going
to the task you prefer to be done first, next lower to the task to be done
next, and so forth. Since there is a 2 day delay on the fixture due to its
repair, I'd put a SNET constraint on the "Install Fixture" task of the date
it's promised to get back to your site from being repaired - can't start its
installation until its delivered. All 4 tasks link in turn to the "Finish"
milestone resulting in 4 parallel chains of start->action task->finish in
your project. Assign your resource and resource level. You're done, a
nicely sequenced and flexible plan. If something changes after work starts,
like you had paint before trim but the resource started trim first anyway,
all you need do is enter actual work on the tasks when it was actually done
and do a "Reschedule Uncompleted Work To After [status date]" and everything
gets updated and resequenced properly.


Of course, since you don't have to either a) coordinate the activities of a
set of different resources with different skills; or b) micromanage your
resource's workday; you could just coalesce all 4 tasks into 1 task "Redo
Bathroom" with a duration of 20 days and let the resource organize his own
work approach - he should be perfectly capable of doing that without your
having to hand-hold him through the process telling what order to do the
various components.
--

Steve House [Project MVP]
MS Project Trainer & Consultant
Visit http://project.mvps.org/faqs.htm for the FAQs
 
G

gueb

Well I am not opposed, but i looked at the Trevor Rabey arguments and i am
still confused. But i tested it it seems to works, but for a big plan, you
need to work with priority a lot (if some task need to be done before
others).

Thanks!
 
S

Steve House

Can't think of anything to add, Trevor - you're correct. It seems some
people think identifying the CP is the end-all and be-all for project
scheduling. It's important, yes, but it's not the complete picture.
Something I've noticed in a number of my students is they (or their bosses)
think that the right software and right techniques can somehow create
self-managing projects where the PM's job becomes one of monitoring and
reporting, making PM essentially a clerical function. Understandable wish,
but misguided.
 
G

gueb

OK, what i learned:

- never use predecessor if the task is not a real predecessor (roof vs wall
is ok) because it will cause you other problems later
- so, when you have a non predecessor case but want to see all task done one
after the other by the same resource, use leveling (and play with priority to
select the order)

Now a last question with leveling. It seems great for a simple project, but
in a bigger project, how the critical path will be affected if a level only a
part of the project (100 tasks, all predecessors are good but 25 task in the
middle need to be leveled).

From the beginning, i used small sample project to explain my problems. Now
i'm changing my real project to update it with your advise, but it seems hard
to follow and exploit after all when you mix both way (levelling and
predecessor)

Is the simple solution is to still use non-real predecessors, but when
something change (need to start a task before the time) i change my task
order and redo the baseline? Is it the primary goal to redo the baseline?

Thanks you so much for your help and happy new year
 
S

Steve House

Nope - the methodology will remain the same regardless fo scale of the
project, in fact IMHO it's even more important in large real-world projects
than it is in small demonstration examples.

Baselines - just the opposite of what you state. You should never redo the
baseline unless the project materially changes - ie, deliverables changed
necessitating tasks be added or removed essentially turning it into a
different project altogether. Tasks that start or finish on different dates
than scheduled, or that take more or less time than originally scheduled,
are variances in the plan rather than a new plan and one of the purposes of
the baseline is to preserve the original schedule so you have a constant to
measure such variances against. Rebaselining destroys any meaningful
performance and progress tracking data because you no longer have any
information as to what your original intent was.
 

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