BPI-6 Sigma: The Measure Phase
| |
Morris Williamson
Mr. Williamson has a bachelors degree in Mathematics,
a masters in Statistics, and a masters in Management Science.
He has 30+ years experience in quantitative methods, is
Adjunct Faculty in Mathematics with Austin Community College,
and has been a trainer in BPI with Dell Inc.
You may contact Mr. Williamson at MWillia900@aol.com. |
|
| |
|
Note: The opinions and views expressed in this BPI series are strictly
those of the author.
Let's briefly review where we are. An operational issue is identified
within the company. We have little knowledge of the underlying cause,
but the issue has big impact upon the company's performance (quality,
cycle time, cost, productivity). Executive staff and the Black Belt
determine the issue to be a good BPI project and approve a BPI team
creation to attack the issue. A contract is developed and signed
off by vertical management indicating support to the project and
team. The contract information is entered into the project database
using the standardized contract format. The team is formed comprising
employees familiar with the issue and who work in the area impacted
(our "sandbox"), the first meeting is held, and various
roles are assigned for the functioning of future meetings (similar
to the dynamics of Total Quality Management; TQM roles are facilitator,
time keeper, scribe, minute taker, etc.). A process map is developed
of the "As Is" process, including decision points, queues,
electronic/hardcopy inputs/outputs, and process notes. All of this
happens in the Define Phase, the first module/phase of the BPI model.
The second phase of the BPI model is the Measure Phase.
Broad measurements (data) should reflect process performance relative
to quality, cycle time, cost, or output (volume), consequently reflecting
the voice of the customer. Remember, the customer is the entity
that receives the output from the process. Since data collection
consumes resources and time, it is important to collect only that
which will be useful in depicting the process dynamics. Data tells
us where we are and where we wish to go! The output measures reflect
the customer's requirements and expectations. This requires the
BPI team to understand who the customer is and their needs and requirements.
By starting with output measures, one can look upstream in the
process to identify measures that support the output and that identify
variability. Variability exists in all processes. We have variability
in the process product and variability in our measurement system.
Before any changes should be made to the process, you should attempt
to squeeze or reduce the process variability and fine-tune the measurement
variability. If you don't, then any changes you make in the process
steps might affect the output only because of the natural variability
that exists, and not because of the changes made. When looking upstream,
our purpose is to identify those vital few input and process factors
that affect the output. This is where we need to focus our attention.
Remember that measures should reflect the process and not an individual's
performance. Measurement provides a feedback regarding the process
behavior, where fine-tuning is required, and where the issue needs
to be analyzed further. Measurement is a key toward improving the
process. I've heard it said, and I agree, that "An opinion
without data, is just another opinion!" And there will be a
lot of opinions regarding the intuitive fix.
The types of data that will be measured will be attribute data
and variable (continuous) data. Attribute data is usually characterized
by countable outcomes and requires a relatively large number of
responses to be useful for analysis. On the other hand, variable
data is more measurement in nature. This type of data is rich for
statistical analysis. A variety of literature (some listed in the
first article)
is available to further define and describe the characteristics
and types of statistical analysis that can be performed using these
types of data. To facilitate the data analysis, statistical techniques
involving sampling (design of experiments, sample size determination,
sampling plans), inferential statistical analysis (confidence intervals
and test of hypothesis) are frequently used. A systematic data collection
process ensures continuity and provides ongoing monitoring of the
process. Training sessions for the data collectors, well-designed
data collection instruments, standardization of terminology and
criteria, how the data reflects the customer requirements, quality
control (QC) charts, statistical process control (SPC) gauge capability
(how good is the measurement system), and other statistical methodologies
provide the pulse of the process that is understudy.
In the next BPI model phase, Analyze Phase, we will look at various
quality tools that assist us in analyzing the process and data obtained
from the process.
|