In this posting we’ll take a look
at the stark differences between CCPM and CPM and why I believe that CCPM is
the superior method. If you have any comments or questions, please leave them in the comments section of this blog and I will respond to them.
In CPM, tasks are over-inflated by at least 50 percent and here’s where we take advantage of this extra time. We now subtract half of the time estimates from each one of the tasks and create a project buffer as in the following figure.
In CPM, tasks are over-inflated by at least 50 percent and here’s where we take advantage of this extra time. We now subtract half of the time estimates from each one of the tasks and create a project buffer as in the following figure.
As you can see, the new
tasks times are half of the original estimates, but you can also see that we
now have added a project buffer. The
project buffer becomes half of the time we have taken from the task
durations. The next question we now posed to leadership
was, how does having this project buffer improve the on-time completion of projects? Surprisingly, one member of the leadership
team was able to give a wonderful analogy to answer this question. The team member said, “If I understand this
concept, then the project buffer works just like a bank account with deposits
and withdrawals. If a task takes longer
than the estimate, you withdraw time from the project buffer, but if the task
is finished in a shorter amount of time, you add the time back into the project
buffer. We told him this was a great
analogy.
With CPM, delays are
passed on while gains are lost and this is such a significant difference! The project buffer protects the project from
delays. We also explained that we also
add feeding buffers to make sure that tasks not on the critical chain are
completed on time.
At this point there was a
question from the leadership team on why we thought that having this project
buffer would eliminate the Student Syndrome and Parkinson’s Law and we answered
this question in the following way. In
traditional project management, that is using the Critical Path Method (CPM),
each task has a scheduled start and finish date. CCPM completely removes the start and finish
dates from the schedule so that the focus will be passing on tasks as soon as they
are completed. In doing so, both the Student Syndrome and Parkinson’s Law are
pretty much neutralized. We explained that CCPM uses a relay race mentality
whereby the runner completes a certain distance and then passes off the baton
to the next runner who is waiting.
Earlier I explained that in CPM
we track progress of the project by calculating the percentage of individual
tasks completed and then comparing that percentage against the project due date.
The problem with this method is that it
is nearly impossible to know how much time is remaining to complete the project.
If you use this method to track
progress, many times you’ll see 90 percent of a project completed only to see
the remaining 10 percent take just as long. In fact, looking at the number or
percentage of tasks completed, instead of how much of the critical path has
been completed, only really serves to give a false sense of schedule conformance. CCPM measures project performance in a much
different way, and in so doing, allows the project to make valuable use of
early finishes of tasks. CCPM uses something called a Fever Chart, which is
simply a run chart of the percentage of the critical chain completed versus the
percentage of project buffer consumed. In the figure below, you’ll see three different
colored zones. We explained the
different colors as follows: Green means
that the project is progressing either on or ahead of schedule; yellow means
that the project is using more buffer than progress is being made and that it’s
time to develop a plan to reduce the rate of buffer consumption. Red means that buffer is being used at an
alarming rate and that if no action is taken, the project will definitely be
late.
In order to reinforce the
interpretation of this color scheme, we then asked the leadership team if it
was ever acceptable for your project to finish the project in the red on the
fever chart and virtually everyone said no, except for one person. We then asked, this person to explain under
what circumstances that it would that be acceptable.
The response was that ss long as
the critical chain is 100 percent completed, and you haven’t used more than 100
percent of your project buffer, then finishing in the red is perfectly
acceptable. We agreed and told them that
in fact, if both of these variables are at the 100 percent level, the project
is exactly on time.
It was very important that
the leadership team understood how to interpret the fever chart, so we then
asked for a volunteer to explain what they saw on this fever chart. Some did volunteer and explained it very
well. Tis project started off ahead of
schedule by completing 20 percent of the critical chain while only consuming 8
percent of the buffer. But if you look at the latest data point, only 41
percent of the chain is complete, but 72 percent of the buffer has been consumed,
This project is now behind schedule, and unless some kind of intervention is
undertaken, this project will be late.
It doesn’t mean that this project is doomed to be late, but rather it
only means that some kind of action must be taken, or the project will be late
completing.
The key point to remember
here is that you should get excited with vertical rises because it always
spells trouble if left unattended, In
addition, we explained that if you divide the percent of the critical chain
completed into the percent of buffer consumed, this ratio could give a single
number that would tell you how well you’re doing. So if your ratio was above one, your rate of
buffer consumption would be too high, while if the ratio is below one, everything
is going well. This was important for
the leadership to understand because they would not have to review every fever
chart for every project. They could
simply look at the ratio for each project and know if it was on schedule or whether
it might need their help.
One other point we presented to the
leadership team was the concept of a portfolio of projects. We presented the fever chart above to let
them know that this was a tool that would allow them to see, at a glance, which
projects might need their attention. On
a single sheet of paper or one computer screen, they would be able to see which
projects were red and yellow….those that might need their attention and which
projects that they could ignore (i.e. the green ones). In the above fever chart we asked them which
ones might be in need of an intervention and they all rightfully told us that
projects 1 and 7 were clearly eating up buffer at an unacceptable rate and that
projects 2, 3 and possible 8, might need some work. They also recognized that projects 4, 5, 6
and 9 did not pose a threat, at least for the moment.
There was another side of
the CCPM implementation that we explained to the leadership team, key things
that must be done if their CCPM implementation was going to be successful. We
explained that every day there must be stand-up meetings with the key resources
to find out what their resources might need.. By that we meant that they should
go to the resources and ask them if they have everything they need and if they
have any problems. The leadership team needed to understand that if the “boots
on the ground” executing the projects couldn’t resolve their issues, then they
must escalate the problem up through the various levels of management. We explained that although this may sound
trivial, it truly isn’t and that if this step is not taken seriously, the
implementation will never be sustained.
In my next posting, we’ll take a look at the
results achieved as a result of this implementation.
Bob Sproull
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