Hi, Skip

Up till recently, I was operating in blissfull ignorance relative to task
priority. The reason was that I had made a decision some years ago to be
conservative, and not give credit in the buffer penetration calculation or the %
CC complete for tasks that were completed out of sequence, until the chain was
completed up to that point.

I recently decided to change that, because in some cases it was far too
conservative. (people were able to do buffer recovery by completing tasks out of
sequence, and were bummed that they could not see the result), and because I
decided to implement the "chain view" to aid buffer recovery planning.

The choice opened up a can of worms. Maybe more like a bucket.

I did know all along that for a given Task Manager, task priority does not equal
project priority, and have preached that as a major benefit of CC. I also know
that as long as people do tasks the right way (relay racer focus), they will get
the most benefit from CC...even if they do them in the "wrong" sequence. The
reason is that all tasks get done sooner when done with focus.

But I didn't know the nicities of the buffer impact calculation, because of the
simplifying assumptions I had been using.

Yes, Concerto plots prgress vs. the "longest chain", which sometimes, though not
usually, is other than the critical chain. I don't think they redo the whole CC
calculation, though, each time they run "buffer management"; e.g. releveling,
identifying a new CC, and inserting feeding buffers in new locations. I have no
idea what the other CC softwares do on this.

One of the other things I am dealing with is what to do during status; i.e.
calculation of task buffer impact, with the gaps that were part of the initial
schedule. As most probably know, CC schedules have gaps in them from two
sources; resouce leveling and insertion of feeding buffers. The first are on
feeding chains, and the latter on the CC. Anyhow, the two basic choices during
status are to keep the gaps, or to do away with them.

I'd appreciate thoughts on the above.

Regards,
Larry Leach








--- In CriticalChain@yahoogroups.com, "Skip" <skip@...> wrote:
>
> Larry,
> I got the questions.
> I don't have Concerto on my computer at the moment. I modeled it with
> Sciforma PS8. I expected the project buffer penetration to go back to zero,
> but it didn't. Very interesting.
> Skip
>
> _____
>
> From: CriticalChain@yahoogroups.com [mailto:CriticalChain@yahoogroups.com]
> On Behalf Of Lawrence
> Sent: Tuesday, July 14, 2009 12:16 PM
> To: CriticalChain@yahoogroups.com
> Subject: [CriticalChain] Re: Buffer Penetration
>
>
>
>
>
> Hi, Skip
>
> Yes, you missed the two operational questions:
>
> 1. What is "the" project buffer penetration, to be used in deciding on
> action?
>
> 2. What are the task buffer penetrations, to be used in task priority.
>
> Regards,
> Larry Leach
>
> --- In CriticalChain@ <mailto:CriticalChain%40yahoogroups.com>
> yahoogroups.com, "Skip" <skip@> wrote:
> >
> > If the out-of-sequence task that was worked is on the critical chain and
> > began with all its necessary inputs, then it has become part of the
> critical
> > chain that is complete. Therefore, 5 days of buffer has been recovered.
> > There is nothing magical about the sequence of critical chain tasks unless
> > there is a true dependency. If it is only a resource dependency, the order
> > they are worked is not important.
> >
> > If the out-of-sequence task was not on the critical chain, then it only
> > counts for its feeding chain. This would be where Earned Value says the
> > project is more completed, but Critical Chain Project Management would
> not.
> >
> > This seems straightforward. Did I miss something?
> >
> > Skip Reedy
> >
> > _____
> >
> > From: CriticalChain@ <mailto:CriticalChain%40yahoogroups.com>
> yahoogroups.com [mailto:CriticalChain@
> <mailto:CriticalChain%40yahoogroups.com> yahoogroups.com]
> > On Behalf Of Crispin ("Kik") Piney
> > Sent: Monday, July 13, 2009 11:29 PM
> > To: CriticalChain@ <mailto:CriticalChain%40yahoogroups.com>
> yahoogroups.com
> > Subject: RE: [CriticalChain] Buffer Penetration
> >
> >
> >
> >
> >
> > Larry,
> >
> > I think this is a classic Earned Value discussion.
> >
> > Kik
> >
> > Crispin ("Kik") Piney, PgMP
> >
> > kik@PROject- <mailto:kik%40PROject-beneFITS.com> beneFITS.com
> > +33 (0)680 11 57 77
> >
> >
> > _____
> >
> > From: CriticalChain@ <mailto:CriticalChain%40yahoogroups.com>
> > yahoogroups.com [mailto:CriticalChain@
> > <mailto:CriticalChain%40yahoogroups.com> yahoogroups.com]
> > On Behalf Of Lawrence
> > Sent: 14 July 2009 00:20
> > To: CriticalChain@ <mailto:CriticalChain%40yahoogroups.com>
> yahoogroups.com
> > Subject: [CriticalChain] Buffer Penetration
> >
> > Hi, All
> >
> > When you think about it simply, buffer penetration is a pretty simple
> idea.
> > For example, you can compare where a task is projectd to end, and subtract
> > from that where it ended in the baseline plan, and you have the buffer
> > penetration for that task. The largest buffer penetration in the project
> is
> > what you plot on the fever chart.
> >
> > Or maybe it isn't quite that simple?
> >
> > Consider, for example, doing tasks out of sequence. While that may seem
> like
> > it should not happen, as there was a reason to do them in a particlar
> > sequence to start, suppose that sequence was simply to level the resource
> > demand. Then, in execution, in order to recovery buffer, you assign a
> > different resource, and do a downstream task early. Complete it! What is
> the
> > buffer penetration of the task that follows it?
> >
> > Let me make it more concrete. Consider a task on the critical chain, that
> is
> > now workinig, and is projected (with remaining duration) to finish 5 days
> > later than it was scheduled in the baseline plan. The project buffer is 20
> > days.
> >
> > As part of early buffer recovery, the next 5 day task in the chain has
> > already been completed (out of sequence), by assigning another resource to
> > it.
> >
> > In this case, what should be plotted on the fever chart? What should be
> used
> > as the priority (buffer impact) for the successor to the completed task
> when
> > comparing task prioirty for a given resource assigned to tasks on several
> > projects?
> >
> > Regards,
> > Larry Leach
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>
>
>
>
>
> [Non-text portions of this message have been removed]
>