Larry, if I understand correctly, CCPM applies a somewhat modified PERT- approach to activity duration estimates. The underlying central limit theorem however,...
Though I really appreciate the insightful theoretical discussions on special vs. common-cause let me suggest the following practical view: (1) There is one...
Hi, David I feel The Force beginning to recover from the brink of chaos... One can get too pedantic about anything. Indeed, people almost always do. One way I...
Hi, Christian If not, make another assumption. As a project manager, you have the power! A common assumption is to assert that any bias experienced to date ...
Hi, Christian Thanks for a thoughtful input! I'm OK with keeping it at two categories, though. Those within the tasks, which I am calling common-cause, and...
Hi, Richard Data is one way to identify special-causes...not the only way. Althoug Deming notes there is hazard in other ways, we have to deal with the hand we...
Hi, Richard Well, at least we agree on one thing! ;-) Regards, Larry Leach, PMP ... special causes on critical chain projects, the measurement system is ...
Let's assume we've to manage a project with three activities A, B, and C to be performed in a strictly sequential mode: Activity A – duration (mean) – 10...
Why do you need to adjust? As I can see in your example, the three events are independent regarding the causes for their variation, so that it's very unlikely...
With regard to Christian's question: The buffers are assigned at the project or chain level to get us out of the problem where every task has its own buffer...
... "David J. Anderson" <netherby_uk@...> Hence, the concept of uncontrolled variation is not synonymous with assignable cause but Deming clearly uses...
Rob Newbold wrote: But it's true, I couldn't come with a good reason why 50% buffers are "reasonable," other than through empirical evidence. In fact, in some ...
The (only ) advantage of the 50% buffer (and I think it is the reason of its existance) is that it is simple for quick calculations or presentations, and it...
With respect Richard, you are clearly on a completely different wave length. The specification limit for a project is the project promise (which presumably has...
"David J. Anderson" <netherby_uk@...> wrote: With respect Richard, you are clearly on a completely different wave length. The specification limit for a...
We're just going to have to disagree on this! If you can't come around to the notion that the promise - whatever it is and however loose or tight and however ...
... "cutting ... I thought we had beaten this horse enough, but in poking around some old emails I found one from Frank Patrick from the APICS list (1999) with...
Richard - ... And ... be. ... fine. ... My experience is that this depends on how buffer sizing is presented. If the statistical theory is presented...
... Hi, sorry about the delay in responding. I did start writing something towards answering your question but got side-tracked. I suggest you take a look at...
... solid explanation of buffer sizing. My experience is that this depends on how buffer sizing is presented. If the statistical theory is presented...
... Looks like I haven't been able to get my point across ... sorry about that. What I'm really looking for is an answer to the question of HOW to create...
... <Richard@Z...> wrote: [REZ>] I don't see ANY use for common and special causes in PLANNING a CC project. [They are important if you are going to do process...
Richard - ... haul, ... of ... Actually, I was referring to 50% buffer sizing, which in the default case seems to be what you call the "1/3 estimate." ... ...
Christian: I find that the fever charts that came up on this group a while back tell the story in a way that is pretty easy to understand (and also gives you...
... back tell the story in a way that is pretty easy to understand (and also gives you the trend analysis that perhaps goes to the heart of the special vs...
Hi, Just saw this item on yahoo news and checked the website. http://www.openworkbench.org/. This seems to be mature project management tools. Does anyone know...
