Hi there. My name is Ron Pereira and I’d like
to officially welcome you to this first overview module of the Gemba
Academy 7 QC tools course. By the end of this module you’ll know what
quality control is, you’ll understand the benefits of quality control,
and you’ll know what the 7 QC tools are. You’ll also begin to see how
the 7 QC tools can help your organization improve
no matter what type of work you do. To be sure, you don’t have to manufacture
widgets to practice quality control as we’ll learn throughout the rest of this course.
Okay. Well let’s get things started by offering a definition of quality control.
And to do so we’re going to hear from one of the giants of quality control,
Dr. Kaoru Ishikawa, the person credited with defining what we call the 7 QC Tools today.
Well when asked to define what quality control was, Dr. Ishikawa
said, “…that it consists of developing, designing, producing, marketing,
and servicing products and services with optimum cost-effectiveness and
usefulness which customers will purchase with satisfaction.”
Now from this definition it’s clear that Dr. Ishikawa felt quality control
was far more than visually inspecting parts at the end of the assembly line.
In fact, Dr. Ishikawa often spoke of Total Quality Control or TQC which
saw quality control spread to all facets of the organization
including front office tasks. So that’s what it is. Now let’s now
turn our focus to the benefits of quality control.
First, when quality control becomes a way of life the number of defective products will
decrease and as such, over time customer satisfaction will
increase leading to enhanced trust and loyalty. And from an internal perspective,
consistent quality control lowers costs for the company since people
aren’t wasting time reworking parts and waiting for good parts to be produced and, as such, profits increase year
over year. So you see, done correctly, quality control
reaches all aspects of our business which results in happy and loyal
customers. Now then, the tools most often used for problem
solving by organizations well versed in quality control are called
the Seven QC Tools. Now for the rest of this module, we’ll take
some time to introduce them and then throughout the rest of this course
we’re going to be taking a deep dive into each tool explaining how they can be applied
in both manufacturing and transactional environments.
But before we get into the tools, I’d like to provide a little background on
how these concepts developed. And as it turns out, the Japanese began applying
quality control during the 1930’s and 1940’s after Dr. Walter Shewhart
and Dr. W Edwards Deming introduced the concepts. Dr. Kaoru Ishikawa,
the then head of the Japanese Union of Scientists and Engineers decided to expand
the use of these tools in the 1960’s with the introduction of what
we now call the Seven Quality Control Tools. Dr. Ishikawa chose
these 7 tools as a way to make the use of quality control accessible
to anyone, no matter their experience with statistics.
Well the first of the 7 QC tools is the graph. Now most of us have seen or used graphs at
one time or another. With graphs, data are expressed to easily
compare quantities or quantity changes. They’re also used for arranging data, sharing
information with others, and making judgments. Now in our next module,
we’ll not only explore several different types of graphs, but we’ll also
explain how to choose the correct graph to use. The second
QC tool is the Check Sheet which are tables used to arrange data
by type. Now we also use these simple, but powerful
tools, for checking if jobs are completed without problems and for
preventing mistakes from happening at all. The third
QC tool is the Pareto Chart. Now Pareto Charts classifies problems and
defects by type in the order of quantities and shows the cumulative total.
Now Pareto Charts are often used for checking a problem or defect to be highlighted for
solution. In other words, Pareto Charts often help us
identify where the problem is as we learned about in the Gemba Academy
Practical Problem Solving course. Again as a reminder, Pareto charts get their
name from Wilfredo Pareto, the Italian economist who was the first to
identify the so called 80-20 rule. Well the fourth tool invented by the aforementioned
Dr. Ishikawa is the Cause & Effect diagram, sometimes called
the fishbone. Now the cause and effect diagram systematically
arranges the results of effects and the factors that influence
them. With this information, we’re able to classify causes
and their potential influence on the problem at hand. The fifth QC tool
is called the Scatter Diagram which is a graph used to examine
the correlation between variables by plotting corresponding data.
In other words, Scatter Diagrams help us examine the relationships between
two variables and whether or not they’re associated, or correlated,
with one another. Now, we’ll get into different variations of
the Scatter Diagram including regression later in the course, but I do want
to mention an extremely important aspect of studying correlation.
Namely that correlation does not automatically mean there is causation. Now
an example of this is how in some cases it can be statistically shown that as the number
of liquor stores in a town increases so do the number of churches
built. So one could conclude that if a town hoped to have more
churches all they need to do is build more liquor stores, right?
Well of course this is complete nonsense since the two, liquor stores and churches,
aren’t correlated at all. Now a better explanation for this situation
is that as a town grows in population , there’ll be some who like to visit liquor
stores and some who like to attend church. Next, we come to the
Histogram which is a graphical display of numerical data in
the form of upright bars. With histograms, we’re able to learn many
things including how much variation, or spread, a data set contains. Now when we
add in customer specification limits, which we’ll learn more about later
in the course, we’re able to calculate something called Cp and Cpk which basically
tells us how well our process meets customer requirements. And last
but certainly not least, we come to the Control Chart which is a tool
used for judging the situation of quality values against control limits in order to
check the stability of a process. Now Control charts also help us to understand
whether we’re dealing with common cause or special cause variation which is
an extremely important information to know as we work to control quality across
all levels of the organization. Now we first learned about common cause and
special cause variation in our Practical Problem Solving course, but as a
quick refresher common cause variation could be likened to the normal everyday traffic
we experience on our commute each day to work. And special
cause variation could be likened to when there’s an accident and traffic
comes to a complete stand still. Alright. Those are the 7 QC tools. As promised
throughout the rest of this course, we’re going to take a deep dive
into each one separately explaining how the tool can be applied in both manufacturing
and transactional environments. Additionally, throughout the rest of this cours,e we’re
going to learn how to create each of these tools using Microsoft
Excel and Sigma XL statistical software.
Alright, well this wraps up this overview module. In our
next lesson, we’re going to dive right into things as we gain a deeper
understanding of the many different kinds of graphs available to us.
So we’ll speak to you soon.