Critical Path

[emq_33]

In creating my schedule in MS Project (2007), I probably violated
about every rule there is for creating it the right way. Let's just
chalk it up to bad luck on a number of fronts!

So, the problem:

I am trying to identify the critical path in the schedule and the only
thing that currently shows as being on the critical path are three
tasks smack dab in the middle of the schedule. The tasks are
sequential with the first being a predecessor of the second, etc. The
first task is preceeded by a milestone event ("Initiate
Development"). This construct occurs a couple of places in my
schedule.

However, I do have a final event ("Final Delivery") which has multiple
predessesors. I would expect the critical path to end with this
milestone and be part of the highlighted path. The tasks which are
currently highlighted as being in the critical path are indirect
predecessors of the "Final Delivery" milestone.

Even using the Gantt Wizard to define the critical path does not help.

Now for some of the probable rule violations:

* When the schedule was originally built, it was laid out as tasks
with fixed start and end dates. Predecessors were defined. The tasks
have since been converted to fixed duration and "start as soon as
possible".

* There is no single milestone that defines the start of the schedule
(eg "Contract Award"). Instead there are key activities consisting of
related tasks that start with an "Initiate Development" type
milestone.


The upsides?

* I am the only one who uses the schedule, so there are no issues
with synching, servers, etc

* It's a "duration" and percent complete schedule, ie no resources,
etc. Probably pretty simple in the bigger picture

* Don't have to baseline

Since I am not sure if this is too little or too much information to
analyze this problem, I will stop here. If more information is
required, just let me know.

Any suggestions on how to highlight the ciritical path will be greatly
appreciated! Or if I am hopelessly hosed over, I would like to know
that too!

Thanks!

Don

 

[Dave]

What does the "late finish" of your last task say compared with the
project end date?

What is driving the dates of your last task and what is it that makes
that task fall on those dates?

What is the interval in "Tasks are critical if slack is less than or
equal to" under Tools/Options/Calculation?

In a levelled plan, there may be periods in which no task is critical
(although that can't apply here as you haven't any resources).

 

[Don]

Dave,

I am a novice/hack with Project, so I am not 100% sure how to answer
some of your questions, but here goes:

1) Well, I am not sure what "late finish" is. The last task
(actually a milestone - "Final Delivery") is set for 2/26/2010 with a
finish no later than date of 2/26/2010 For the project, the end date
is 4/1/10 and is set to schedule from the project start date.
Interestingly, the project finish date seems fixed.

2) The last milestone is driven by the need to deliver to the
customer on that date. Not sure if that is the type information you
are looking for there.

3) The interval value is set to 0.

Q3) Should I be selecting "multiple critical paths"?

Thanks for the help!

Don

 

[Dave]

1) I don't see why the final milestone is being held out at 02/26/2010
if there isn't a task immediately preceding it. If I understand
correctly, the last task ends on 04/01/2010 which is inconsistent with
what you have told me.

Insert the constraint column (right click on the headers in the left of
the Gantt chart and choose "Constraint Type"). Generally speaking,
these should all be "As Soon As Possible".

For a given task, what makes it occur on a given date? Is it there
because a predecessor pushes it out? Or is it there because you have
manually moved it to be there (doing this sets constraints)?

2) I meant what pushes the last task to start on that date? Is it a
constraint or a predecessor relationship?

3) OK

Q3) No.

If you have constraints on your tasks, then the critical path
calculations will be compromised. This is the usual cause of problems
of this nature.

"Late Finish" is a term used within this discipline to indicate the
latest date that a task can start without compromising the project
completion date. For example, if I have a 1-month project and I have a
1-week task which can be done any time in that month, then the late
finish is the last day of the project. Any later and the project gets
pushed out. Similarly the "Late Start" is 1 week prior to that.

You can examine the "Late Finish" dates of your tasks by inserting the
"Late Finish" column.

 

[Mike Glen]

Hi Don,

Welcome to this Microsoft Project newsgroup

Try inserting a column for Total Slack and try to identify why those you
would expect to be critical are not zero. Have a check on your milestones
that they are also As Soon As Possible.

FAQs, companion products and other useful Project information can be seen at
this web address: http://project.mvps.org/faqs.htm

Hope this helps - please let us know how you get on

Mike Glen
MS Project MVP
See http://tinyurl.com/2xbhc for my free Project Tutorials

 

[Steve House [MVP]]

A general rule of thumb is that all projects should have at least a start
milestone and a finish milestone. ALL tasks within the prject should have
at least one predecessor and at least one successor - no "dangling tasks" on
either side. If a task has no activity as its predecessor, the start
milestone is its predecessor. If a task has no successor activity, the
finish milestone is its successor. In other words, ALL tasks lie somewhere
on an unbroken chain of actions extending from project start to project
finish. The may be many pathwyas through the project and the chains of
events may diverge and converge in a web of varying complexity, but no task
stands alone without links into it and out of it.

A Finish No Later Than constraint on your finish milestone will force
Project to show it no later than that date EVEN IF it is physically
impossible for it to actually happen that way given the scheduling of the
other tasks in the project. The finish milestone sitting on Feb 26th but
the last task not finishing until April 1st is a physical impossiblilty
since by definition the project is not finished until all of its component
tasks are finished. Make sure all paths through the project ultimately
converge on the finish milestone, set a Deadline entry on the milestone of
Feb 26 to reflect your required finish date, set it's constraint to ASAP so
Projkect can show you the delivery date you actually will hit if you work
the plan according to the present schedule (April 1st, over a month late if
I read you right) and then tweak and crash your schedule by working on
resource assignemnts, etc, until the computed date of the milestone moves up
to come in before the deadline.
--
Steve House [Project MVP]
MS Project Trainer & Consultant
Visit http://project.mvps.org/faqs.htm for the FAQs




Dave,

I am a novice/hack with Project, so I am not 100% sure how to answer
some of your questions, but here goes:

1) Well, I am not sure what "late finish" is. The last task
(actually a milestone - "Final Delivery") is set for 2/26/2010 with a
finish no later than date of 2/26/2010 For the project, the end date
is 4/1/10 and is set to schedule from the project start date.
Interestingly, the project finish date seems fixed.

2) The last milestone is driven by the need to deliver to the
customer on that date. Not sure if that is the type information you
are looking for there.

3) The interval value is set to 0.

Q3) Should I be selecting "multiple critical paths"?

Thanks for the help!

Don

 

[Don]

Thanks Steve and everyone else. I am still going through my schedule
to try to figure out where I am going a stray. Somewhat classic case
of need the Project data, but have to keep the real work that the
schedule describes moving!

Don

A general rule of thumb is that all projects should have at least a start
milestone and a finish milestone.  ALL tasks within the prject should have
at least one predecessor and at least one successor - no "dangling tasks"on
either side.  If a task has no activity as its predecessor, the start
milestone is its predecessor.  If a task has no successor activity, the
finish milestone is its successor.  In other words, ALL tasks lie somewhere
on an unbroken chain of actions extending from project start to project
finish.  The may be many pathwyas through the project and the chains of
events may diverge and converge in a web of varying complexity, but no task
stands alone without links into it and out of it.

A Finish No Later Than constraint on your finish milestone will force
Project to show it no later than that date EVEN IF it is physically
impossible for it to actually happen that way given the scheduling of the
other tasks in the project.  The finish milestone sitting on Feb 26th but
the last task not finishing until April 1st is a physical impossiblilty
since by definition the project is not finished until all of its component
tasks are finished.  Make sure all paths through the project ultimately
converge on the finish milestone, set a Deadline entry on the milestone of
Feb 26 to reflect your required finish date, set it's constraint to ASAP so
Projkect can show you the delivery date you actually will hit if you work
the plan according to the present schedule (April 1st, over a month late if
I read you right) and then tweak and crash your schedule by working on
resource assignemnts, etc, until the computed date of the milestone movesup
to come in before the deadline.
--
Steve House [Project MVP]
MS Project Trainer & Consultant
Visithttp://project.mvps.org/faqs.htmfor the FAQs



Dave,

I am a novice/hack with Project, so I am not 100% sure how to answer
some of your questions, but here goes:

1)  Well, I am not sure what "late finish" is.  The last task
(actually a milestone - "Final Delivery") is set for 2/26/2010 with a
finish no later than date of 2/26/2010  For the project, the end date
is 4/1/10 and is set to schedule from the project start date.
Interestingly, the project finish date seems fixed.

2)  The last milestone is driven by the need to deliver to the
customer on that date.  Not sure if that is the type information you
are looking for there.

3)  The interval value is set to 0.

Q3)  Should I be selecting "multiple critical paths"?

Thanks for the help!

Don

What does the "late finish" of your last task say compared with the
project end date?

What is driving the dates of your last task and what is it that makes
that task fall on those dates?

What is the interval in "Tasks are critical if slack is less than or
equal to" under Tools/Options/Calculation?

In a levelled plan, there may be periods in which no task is critical
(although that can't apply here as you haven't any resources).

- Show quoted text -- Hide quoted text -

- Show quoted text -