I was asked this:
Hello Chris,I really appreciate the PM videos you upload on YouTube. They have been instrumental in understanding PM, according to an analysis of the critical path. However, my Company is going to hire a Critical Chain PM consultant to teach its managers new PM methodology. I have seen videos on YouTube that compare Critical path vs Critical chain, but am unsure how they differ exactly. Is there any insight you can provide on Critical Chain when compared to Critical path? From the incarnations that I have seen, critical path is lambasted as lacking resource information. Any insight you can provide would be much appreciated.Thank you,Przemek
Here is my reply
Yes it’s true that the critical path is based on the critical path diagram which assumes infinite resources. But that is not a problem because later when we make it into a Gantt chart we think about the resources available within that project, and then the third stage is the Gantt of Gantts where we think about the resources of all of our projects added up.
.
So it is just the first part of the process and it is brilliant for that, and should not be criticised because it doesn’t do the whole job in one step. In fact it would be too hard to do the whole job in one step, you have to break it down into manageable steps in order to solve the problem
.
The only objective of finding the critical path is to decide on the running order of the tasks – and then to find out how quickly in theory we could do the project. Sometimes even the theoretical quickest time is still too long for the customer, and then we know we have a problem
.
The critical chain on the other hand takes into account shortage of resources at an earlier stage in the PM planning process. It will get you to the same point if you do it correctly – but I think working out the critical chain is really quite difficult. I would be interested to see if they’ve got an easy way to do it.
.
If you can do the critical chain correctly it will get you to the same result as my method = the method used by the Association of Project Managers = the method used successfully for 100 years by everyone who has made any significant size of project in that time
.
There will always be consultants selling the latest thing and I think the critical chain is a variant on the traditional message that is clever but also confusing and not really needed
.
There is a book on the critical chain by Eli Goldratt which is interesting. But it doesn’t quite tell you how to actually calculate the critical chain.
Goldratt is a God because of his book The Goal – which is about processes not projects, and I think he was struggling for his next idea and I don’t think he quite hit the nail on the head the second time. Sorry Eli!
.
So the critical chain is trying to solve a problem that isn’t really there. The only thing I don’t know is how neat their methodology is for working it out but I suspect it’s not really possible to work out the critical chain for one project without taking into account all of the other projects, and I think that would be incredibly difficult.
.
Much better to do my Gantt of Gantts,
.
see here for how to do one of those
.
.
regards
.
CC
