Both KM and Six Sigma are built on best practices that
have emerged through decades of work.
The beauty is that they are complementary and
should be integrated. KM can add sustainability to process improvement. Organizations
frequently "forget the recipe" as time passes and employees move on. Fifty
percent turnover in some industries means that, without a knowledge capture and
reuse approach, the process will degrade. Often, a Six Sigma team comes in and
repairs the process and then leadership moves on to the next project. However,
just because a process is "fixed" doesn't mean that newcomers know how to
operate within the process. This is where communities of practice come in: CoPs
are designed to steward processes and bodies of knowledge over time, so a community
is an ideal structure to own the initial process redesign as well as the
continuing improvement and lessons learned. To sustain success over the long term,
methodologies like Six Sigma need the people-process orientation that KM
provides.
On the other hand, KM needs the rigor that Six Sigma
(or any disciplined process-improvement methodology) can supply. KM
practitioners should understand what really drives the process and where
knowledge is the variable that needs to be managed. Additionally, KM benefits
from the measurement rigor that Six Sigma can bring. Six Sigma focuses
strongly on outcomes and tangible evidence of impact on the business.
Today, so many of our processes are global, very
complex, and knowledge-intensive. When organizations recognize that knowledge resides in
people, they can bring together the best of KM and Six Sigma, combining the
explicit knowledge about a specific process with the deep tacit knowledge required
to link people to the information they need to correctly perform the process
and benefit from the lessons learned.

Great post.
I was talking to a client yesterday about the need to get away from a rigid enforcement of global standards (compliance) and incorporate some opportunities to innovate within strategic guidelines identified by six sigma (performance). There's an HBR article I referenced in our meeting that addresses this as process vs. practice - "Balancing Act - How to Capture Knowledge Without Killing It" by Seely Brown and Duguid - and he really resonated with that message.