Deadline markers and critical path

[Mary Ann]

When I add a deadline marker to my End Project milestone and set the deadline
date as the end project date + 2, there is no longer a critical path. I
understand this is because the tasks now have total slack.

When I add a deadline marker to a task which is on the critical path, say
half way through the project, the critical path remains. Following the logic
of the example above, I would have thought the earlier tasks would now have
total slack and therefore not show a critical path for that part of the
project.

When do deadline markers impact the critical path and when not?

 

[Haris Rashid]

hi Mary Ann,

Deadlines affect the calculation of late finish dates, the backward pass,
and the total slack of a task. The deadline usually sets the late finish for
a task and thus affects the backward pass.

When you set the deadline of the project forward from the "calculated"
finish date, the late finish date of the last task is changed and the
critical path is lost because every task has a slack.

However when you apply the deadline to a task somewhere in the middle the
late finish date might not change given the linked tasks and how project
claculates late finish date. When you first create a task, its late finish
date is the same as the project finish date. As you link the task to
predecessors and successors and apply any other constraints, Project
calculates the late finish date as the latest possible date this task could
be finished if all predecessor and successor tasks also start and finish on
their late start and late finish dates. These calculations are based on a
fixed task duration.

Because of the successor tasks when the late finish date is not changed the
critical path remains intact.

Kind regards,

 

[Mary Ann]

Thanks Haris. What is the backward pass??

hi Mary Ann,

Deadlines affect the calculation of late finish dates, the backward pass,
and the total slack of a task. The deadline usually sets the late finish for
a task and thus affects the backward pass.

When you set the deadline of the project forward from the "calculated"
finish date, the late finish date of the last task is changed and the
critical path is lost because every task has a slack.

However when you apply the deadline to a task somewhere in the middle the
late finish date might not change given the linked tasks and how project
claculates late finish date. When you first create a task, its late finish
date is the same as the project finish date. As you link the task to
predecessors and successors and apply any other constraints, Project
calculates the late finish date as the latest possible date this task could
be finished if all predecessor and successor tasks also start and finish on
their late start and late finish dates. These calculations are based on a
fixed task duration.

Because of the successor tasks when the late finish date is not changed the
critical path remains intact.

Kind regards,

 

[Gérard Ducouret]

Hello Mary Ann,

Backward pass : you calculate all the late dates : Late Finish and Late
Start, from the end of the project.

Gérard Ducouret

 

[Mike Glen]

Hi Mary Ann,

Welcome to this Microsoft Project newsgroup

Please see FAQ Item: 42. Guide to Network Analysis

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
Project MVP

 

[Haris Rashid]

hi,

Backward pass is the calculation of the latest finish times by working from
finish to start for the uncompleted portion of a network of activities. Where
network of activities is the logical order of tasks that defines the sequence
of work in a project. Networks are usually drawn from left to right, with
lines drawn between to indicate the precedence between tasks. Arrow heads are
often placed on the lines to indicate the direction of the flow through time.

Following is a link to an article on Microsoft web site where you can
explore more about project scheduling:

http://office.microsoft.com/en-us/assistance/HA010211711033.aspx

Kind regards,

 

[Mary Ann]

Thanks for your reply - very useful website

Hi Mary Ann,

Welcome to this Microsoft Project newsgroup

Please see FAQ Item: 42. Guide to Network Analysis

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
Project MVP

 

[Mary Ann]

Thanks Gerard

Hello Mary Ann,

Backward pass : you calculate all the late dates : Late Finish and Late
Start, from the end of the project.

Gérard Ducouret

 

[Mary Ann]

Thanks Haris - very clear

hi,

Backward pass is the calculation of the latest finish times by working from
finish to start for the uncompleted portion of a network of activities. Where
network of activities is the logical order of tasks that defines the sequence
of work in a project. Networks are usually drawn from left to right, with
lines drawn between to indicate the precedence between tasks. Arrow heads are
often placed on the lines to indicate the direction of the flow through time.

Following is a link to an article on Microsoft web site where you can
explore more about project scheduling:

http://office.microsoft.com/en-us/assistance/HA010211711033.aspx

Kind regards,

 

[Mike Glen]

You're welcome, Mary Ann

Mike Glen
MS Project MVP