Lalit Kumar JainProject Management Consultant & Trainer| Visiting Professor, Poornima University, Jaipur, Rajasthan(India)Dubai, Dubai, United Arab Emirates
On page 190 of PMBOK6, the description of "Start to Finish" is incorrect.
This concept can be explained step wise as follows:
a) For a project scheduler, the Predecessor means "main" activity and "Successor" means subordinate activity. In other words, Predecessor is the "DECIDING" activity even if it is happening later in time.
b) In the example given in PMBOK6, page 190, the new accounts payable system is the "Predecessor" and the old accounts payable system is the successor. The start of new system will "DECIDE" or "DICTATE" the shutting down of old system. So the second sentence in incorrect.
c) There can be a lead or lag in this relationship also. Let us imagine a cricket match has been scheduled from 25th of Oct 8 AM and the watering of ground should stop 48 hours before that, which means on 23rd Oct morning. However, due to any reason if the cricket match gets postponed to 30th Oct, then the watering of ground should stop on 28th Oct.
d) However, as per the wording in PMBOK6, the watering will continue till 25th Oct (or 30th Oct) when the players are entering the stadium. Only when players have started playing, the watering of the ground should be stopped as per the PMBOK6 wording.
e) I want to add a diagram but there is no option to attach a file. Saving Changes...
I'm looking at my copy of the PMBOK version 6 now. For Start to Finish, it states "A logical relationship in which a successor activity cannot finish until a predecessor activity has started. For example, a new accounts payable system (successor) has to start before the old accounts payable system can be shut down (predecessor)."
This appears to be correct to me. Perhaps it's a typo in your copy? Saving Changes...
Senior Projects Manager | Field & Marten AssociatesNew Westminster, British Columbia, Canada
Finish to Start mean the successor (Following Activity) can’t start before the Predesessor is complete (The Activity before that is logically connected to the successor). Sometimes you can introduce leads and lags but that a totally different formula. Saving Changes...
Lalit Kumar JainProject Management Consultant & Trainer| Visiting Professor, Poornima University, Jaipur, Rajasthan(India)Dubai, Dubai, United Arab Emirates
Dear Friends, I give this scenario to you. I have to start wood work in my building and the wood must arrive exactly 2 days before start of the wood work. In case the wood work is delayed due to any reason, then the arrival of wood also must be delayed accordingly so that the wood does not lie in the open and get spoiled. In this case, there are 2 activities - "start of wood work" and "arrival of wood". Please make a sample program in Microsoft Project or Primavera and send me a screen shot on [email protected] . I can send screen shot of my solution if you write your email address. Regards Saving Changes...
Rami - That is incorrect. You are referring to a finish to start relationship. (I can't sit at your desk until you have left it.)
A start to finish relationship is where the predecessor can't be completed until the successor starts. (You can't leave your desk until I have arrived to take over.)
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1 reply by Rami Kaibni
Oct 19, 2018 1:23 PM
Rami Kaibni
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You are correct, I got confused with the explanation given. Thanks for noting this Keith.
Senior Projects Manager | Field & Marten AssociatesNew Westminster, British Columbia, Canada
Oct 19, 2018 12:24 PM
Replying to Keith Novak
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Rami - That is incorrect. You are referring to a finish to start relationship. (I can't sit at your desk until you have left it.)
A start to finish relationship is where the predecessor can't be completed until the successor starts. (You can't leave your desk until I have arrived to take over.)
You are correct, I got confused with the explanation given. Thanks for noting this Keith. Saving Changes...
Lalit Kumar JainProject Management Consultant & Trainer| Visiting Professor, Poornima University, Jaipur, Rajasthan(India)Dubai, Dubai, United Arab Emirates
Keith: Can you please enter the scenario I sent above in any scheduling tool and send me the screen shot? Or send me your email address.
I will give u one more scenario. I want to pour concrete in foundation at 6 PM. As I need a lot of trucks of concrete, I want the trucks to arrive just in time, let us say 15 minutes before pouring, that means at 5:45 PM.
Due to any reason if the pouring activity is late by 2 hours, then the arrival of trucks should also be delayed by 2 hours.
Now in this scenario, which is Predecessor? It is the "pouring of concrete", although it is happening later in time. Which is Successor? It is "arrival of concrete trucks". What is the relationship? it is Start of "Pouring" to Finish of "arrival of trucks". The pouring time is deciding the arrival time of trucks and not the other way round. If the truck comes at 5 PM, it does not mean I will start pouring at 5 PM. Saving Changes...
In both your cricket match and concrete pour examples, there is a piece missing. Any time you are going to start an activity a fixed time before another activity ends, you need something as a trigger since you can't see into the future as to when that preceding event will actually end.
Cricket match: In order to stop watering 2 days before the match, there must be a go/no-go decision that the match will occur on-time which cues the watering to stop. You couldn't decide the day before the match to slide the match one day, since you can't go back in time to stop the watering earlier. Any rescheduling would need to account for at least 2 days to stop the watering.
Concrete pour: You can't pour until the trucks are there, and the trucks can't leave until they are cued to do so. Some event needs to trigger the trucks. In reality, you would have preparations to pouring as a preceding activity. If the trucks need to leave 15 min before the end of prep, something still could go wrong in that time so the trucks would have to leave at risk if activities continue up until the actual pour. To back off from the end of preparations, either progress could be used, e.g. preparations activity 95% complete triggers the trucks to start, (this could be automated but I don't see that as practical in actual construction) or a milestone would be needed, such as a pre-pour review go/no-go gate.
In all cases, if you are going to start an event at a fixed duration before a future event will occur (in this case the future event is completion of an activity) a decision must be made at or before that fixed duration, as to when that future event will actually occur. This is a good use of milestones in addition to flow bars on a Gantt. The flow bars track the completion of activities. The milestones are conscious decisions as to when to initiate the next activities based on the progress of things yet to finish. Saving Changes...
Start to finish could be very confusing, though it hardly find its place in managing projects, but a very simple example I once got made it very clear and it sticked in; a security guide(let's say at the embassy) who is suppose to finish his duty, can't finish until the next guide who is suppose to resume starts his shift. Until the new guide start his shift, the present guide can't end his shift. Saving Changes...
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