Explanation of Start to Finish relationships

[RichardJ]

Hi,
I'm often asked to explain the Start/Finish dependency relationship and find
myself struggling with the logic and the way that MSP2003 will deal with
tasks that have that type of relationship.

Could someone please provide a 'simple' yet definitive explanation as to
when a SF relationship could be used and how MSP will deal with it?

 

[andy]

Richard, may be a long one but here goes:
a SF link is used when a Successor task has a finish date dependant upon the
Start of its Predessor. any delay in the start of the P will delay the Finish
of the S.

ie body gaurd is hired to protect his boss arriving at a show for 2 hours,
until he is safley seated. if the boss is late and the body guard has started
his work period then he will have to remain longer and the finsih time will
extend. If the BG knew the boss was going to be late beforehand he would turn
up at the revised time and work the two hrs so his shift finished when his
boss was safely inside.

i am sure others may offer a simpler version - but this one came to mind

 

[Jack Dahlgren]

SF relationships can be used when you want to determine the timing of a task
which is prior to, but dependent on another task.

It is not that difficult to imagine if you keep in mind that the predecessor
is the task that determines the scheduling for the successor.

In the example given where a bodyguard needs to show up 2 hours before the
person they are guarding, you need to remember that the arrival of the person
they are guarding is the key thing. Making the body guard show up earlier
won't make that person arrive any earlier.

For this reason SF is of best use in determining when things like deliveries
SHOULD be scheduled. The limitation is that if the delivery never happens
then the predecessor will not move.

SF dependencies have a limited usefulness and I've never seen a case where
they are absolutely necessary. If they confuse you, just don't use them.

-Jack Dahlgren

 

[Dave]

Hi,
I'm often asked to explain the Start/Finish dependency relationship and find
myself struggling with the logic and the way that MSP2003 will deal with
tasks that have that type of relationship.

Could someone please provide a 'simple' yet definitive explanation as to
when a SF relationship could be used and how MSP will deal with it?

It's the trickiest of the four. The example I've used in classes for years
is this:
I take my car to my mechanic and tell him there is a problem with the radio
and it needs new brake pads, and that I have to have the car back by 5 pm.
If the mechanic scheduled his work, he would estimate the time it would
take to do the brake pads, say 30 min. He estimates the radio at 60 min.
Then, he schedules backward from the 5pm deadline, and plans to start
working on my car at 3:30 to complete by 5. In this situation, he is
scheduling backward from 5. So the Start of my task, using the car,
determines the finish of his task, replacing the pads. In turn, the start
of fixing the pads determines the finish of fixing the radio. Ergo, each is
a SF relationship.
Hope this helps in your world.

 

[Shreepad Gandhi]

I had the same confusion about Start to Finish relationships. Thanks Dave. I got it clarified from your explanation.



Dave wrote:

Re: Explanation of Start to Finish relationships
02-Jul-08

On Wed, 2 Jul 2008 05:57:01 -0700, RichardJ wrote:


It's the trickiest of the four. The example I've used in classes for years
is this:
I take my car to my mechanic and tell him there is a problem with the radio
and it needs new brake pads, and that I have to have the car back by 5 pm.
If the mechanic scheduled his work, he would estimate the time it would
take to do the brake pads, say 30 min. He estimates the radio at 60 min.
Then, he schedules backward from the 5pm deadline, and plans to start
working on my car at 3:30 to complete by 5. In this situation, he is
scheduling backward from 5. So the Start of my task, using the car,
determines the finish of his task, replacing the pads. In turn, the start
of fixing the pads determines the finish of fixing the radio. Ergo, each is
a SF relationship.
Hope this helps in your world.

Previous Posts In This Thread:

Explanation of Start to Finish relationships
Hi,
I'm often asked to explain the Start/Finish dependency relationship and find
myself struggling with the logic and the way that MSP2003 will deal with
tasks that have that type of relationship.

Could someone please provide a 'simple' yet definitive explanation as to
when a SF relationship could be used and how MSP will deal with it?

RE: Explanation of Start to Finish relationships
Richard, may be a long one but here goes:
a SF link is used when a Successor task has a finish date dependant upon the
Start of its Predessor. any delay in the start of the P will delay the Finish
of the S.

ie body gaurd is hired to protect his boss arriving at a show for 2 hours,
until he is safley seated. if the boss is late and the body guard has started
his work period then he will have to remain longer and the finsih time will
extend. If the BG knew the boss was going to be late beforehand he would turn
up at the revised time and work the two hrs so his shift finished when his
boss was safely inside.

i am sure others may offer a simpler version - but this one came to mind

:

SF relationships can be used when you want to determine the timing of a task
SF relationships can be used when you want to determine the timing of a task
which is prior to, but dependent on another task.

It is not that difficult to imagine if you keep in mind that the predecessor
is the task that determines the scheduling for the successor.

In the example given where a bodyguard needs to show up 2 hours before the
person they are guarding, you need to remember that the arrival of the person
they are guarding is the key thing. Making the body guard show up earlier
won't make that person arrive any earlier.

For this reason SF is of best use in determining when things like deliveries
SHOULD be scheduled. The limitation is that if the delivery never happens
then the predecessor will not move.

SF dependencies have a limited usefulness and I've never seen a case where
they are absolutely necessary. If they confuse you, just don't use them.

-Jack Dahlgren


:

Re: Explanation of Start to Finish relationships
On Wed, 2 Jul 2008 05:57:01 -0700, RichardJ wrote:


It's the trickiest of the four. The example I've used in classes for years
is this:
I take my car to my mechanic and tell him there is a problem with the radio
and it needs new brake pads, and that I have to have the car back by 5 pm.
If the mechanic scheduled his work, he would estimate the time it would
take to do the brake pads, say 30 min. He estimates the radio at 60 min.
Then, he schedules backward from the 5pm deadline, and plans to start
working on my car at 3:30 to complete by 5. In this situation, he is
scheduling backward from 5. So the Start of my task, using the car,
determines the finish of his task, replacing the pads. In turn, the start
of fixing the pads determines the finish of fixing the radio. Ergo, each is
a SF relationship.
Hope this helps in your world.


Submitted via EggHeadCafe - Software Developer Portal of Choice
Entity Framework 4.0 and the AJAX Autocomplete Extender.
http://www.eggheadcafe.com/tutorial...93a-b290f013f649/entity-framework-40-and.aspx

 

[Guest]

I had the same confusion about Start to Finish relationships. Thanks Dave. I got it clarified from your explanation.



Dave wrote:

Re: Explanation of Start to Finish relationships
02-Jul-08

On Wed, 2 Jul 2008 05:57:01 -0700, RichardJ wrote:


It's the trickiest of the four. The example I've used in classes for years
is this:
I take my car to my mechanic and tell him there is a problem with the radio
and it needs new brake pads, and that I have to have the car back by 5 pm.
If the mechanic scheduled his work, he would estimate the time it would
take to do the brake pads, say 30 min. He estimates the radio at 60 min.
Then, he schedules backward from the 5pm deadline, and plans to start
working on my car at 3:30 to complete by 5. In this situation, he is
scheduling backward from 5. So the Start of my task, using the car,
determines the finish of his task, replacing the pads. In turn, the start
of fixing the pads determines the finish of fixing the radio. Ergo, each is
a SF relationship.
Hope this helps in your world.

Previous Posts In This Thread:

Explanation of Start to Finish relationships
Hi,
I'm often asked to explain the Start/Finish dependency relationship and find
myself struggling with the logic and the way that MSP2003 will deal with
tasks that have that type of relationship.

Could someone please provide a 'simple' yet definitive explanation as to
when a SF relationship could be used and how MSP will deal with it?

RE: Explanation of Start to Finish relationships
Richard, may be a long one but here goes:
a SF link is used when a Successor task has a finish date dependant upon the
Start of its Predessor. any delay in the start of the P will delay the Finish
of the S.

ie body gaurd is hired to protect his boss arriving at a show for 2 hours,
until he is safley seated. if the boss is late and the body guard has started
his work period then he will have to remain longer and the finsih time will
extend. If the BG knew the boss was going to be late beforehand he would turn
up at the revised time and work the two hrs so his shift finished when his
boss was safely inside.

i am sure others may offer a simpler version - but this one came to mind

:

SF relationships can be used when you want to determine the timing of a task
SF relationships can be used when you want to determine the timing of a task
which is prior to, but dependent on another task.

It is not that difficult to imagine if you keep in mind that the predecessor
is the task that determines the scheduling for the successor.

In the example given where a bodyguard needs to show up 2 hours before the
person they are guarding, you need to remember that the arrival of the person
they are guarding is the key thing. Making the body guard show up earlier
won't make that person arrive any earlier.

For this reason SF is of best use in determining when things like deliveries
SHOULD be scheduled. The limitation is that if the delivery never happens
then the predecessor will not move.

SF dependencies have a limited usefulness and I've never seen a case where
they are absolutely necessary. If they confuse you, just don't use them.

-Jack Dahlgren


:

Re: Explanation of Start to Finish relationships
On Wed, 2 Jul 2008 05:57:01 -0700, RichardJ wrote:


It's the trickiest of the four. The example I've used in classes for years
is this:
I take my car to my mechanic and tell him there is a problem with the radio
and it needs new brake pads, and that I have to have the car back by 5 pm.
If the mechanic scheduled his work, he would estimate the time it would
take to do the brake pads, say 30 min. He estimates the radio at 60 min.
Then, he schedules backward from the 5pm deadline, and plans to start
working on my car at 3:30 to complete by 5. In this situation, he is
scheduling backward from 5. So the Start of my task, using the car,
determines the finish of his task, replacing the pads. In turn, the start
of fixing the pads determines the finish of fixing the radio. Ergo, each is
a SF relationship.
Hope this helps in your world.


Submitted via EggHeadCafe - Software Developer Portal of Choice
Entity Framework 4.0 and the AJAX Autocomplete Extender.
http://www.eggheadcafe.com/tutorial...93a-b290f013f649/entity-framework-40-and.aspx

Glad I could help - 2 yrs ago!

 

[Jim Aksel]

I have used the "guarding the boss" analogy several times in expalining SF to
people around the office. We do it with negative lag and FS.

Guard Boss [Start]=[Arrival of Boss Finish]FS-2hrs

Now the argument switches to "but Jim doesn't like negative lag" because it
implies certainty in a future event. True, but it has no material impact
unless the guard has already started guardinng. The only time there would be
a problem is if ithe guard started work after being told his boss would
arrive at 4PM (guard starts at 2PM). Then after 2PM the boss gets delayed
and says the task "Arrival of boss to meeting" will now finish later than 4PM.
--
Jim Aksel, MVP

Check my blog for more info:
http://www.msprojectblog.com

This newsgroup is moving, try here too:
http://social.answers.microsoft.com/Forums/en-US/addbuz/threads

 

[Dale Howard [MVP]]

Shreepad --

In a Start to Finish (SF) dependency, the Start date of a Predecessor task
determines the Finish date of a Successor task. Two examples I commonly use
to show this are:

1. The Start date (and time) of a school exam determines when you must
finish studying.
2. The Start date of a Corporate Shareholder Conference determines when
conference preparation tasks must Finish.

Just a couple of additional thoughts. Hope this helps.

 

[Mike Nellup]

Thanks, that auto-mechanic example is really great. The question is how do I assign this relationship to actual tasks in an enterprise plan?
If the tasks are:
Oil Change (20 Minutes)
-Drain Oil (5 Minutes)
-Replace Oil Filter (10 Minutes)
-Add Replacement Oil (5 Minutes)
Replace Brake Pads (30 minutes)
Fix Radio (60 Minutes)
Customer Pickup @5pm (Fixed Time/Date Task) Milestone

How are these relationships assigned to actual tasks?

 

[Mike Nellup]

Thanks, that auto-mechanic example is really great. The question is how do I assign this relationship to actual tasks in an enterprise plan?
If the tasks are:
Oil Change (20 Minutes)
-Drain Oil (5 Minutes)
-Replace Oil Filter (10 Minutes)
-Add Replacement Oil (5 Minutes)
Replace Brake Pads (30 minutes)
Fix Radio (60 Minutes)
Customer Pickup @5pm (Fixed Time/Date Task) Milestone

How are these relationships assigned to actual tasks?