What do you mean by Reliability? How it is different
from Quality? Explain BATH-TUB CURVE.
What is reliability? We hear the term
used a lot in research contexts, but what does it really mean? If you think
about how we use the word "reliable" in everyday language, you might
get a hint. For instance, we often speak about a machine as reliable: "I
have a reliable car." Or, news people talk about a "usually reliable
source". In both cases, the word reliable usually means
"dependable" or "trustworthy." In research, the term
"reliable" also means dependable in a general sense, but that's not a
precise enough definition. What does it mean to have a dependable measure or
observation in a research context? The reason "dependable" is not a
good enough description is that it can be confused too easily with the idea of
a valid measure (see Measurement Validity). Certainly, when we speak of a
dependable measure, we mean one that is both reliable and valid. So we have to
be a little more precise when we try to define reliability.
In research, the term reliability means
"repeatability" or "consistency". A measure is considered
reliable if it would give us the same result over and over again (assuming that
what we are measuring isn't changing!).
Quality
versus Reliability
A Quality problem?
A Reliability problem?
An Unreliability problem?
Isn't it all about Quality?
True, but at the same time that is also the problem. There are so many
definitions about quality that is has lead to at least confusion. Quality has
to be built into the design, you can not create it during manufacturing. It is
very well known that quality is a top-down issue. If the top-down chain does
not support quality in actively then no quality will be delivered other than by
coincidence. The same is valid for reliability. But one needs to
know
what it is.
Also
quality is too massive to be understood completely by anyone. Quality concerns
organizations, management, services, people, procedures, products, life etc.
There are many books available, too many maybe.
Relia-Easy
limits itself to a specific area , a technical product. It concerns something
touchable, a bike, a car, a TV. With products one needs to distinguish
between Quality and Reliability.
Quality
and Reliability belong together but related to the required activities they
belong to different worlds.
Many companies define
Quality as "conformance to specifications". Unfortunately this is not
true or at least incomplete. There are enough examples known where the product
was exactly
according
to specification but did not satisfy the customers' wishes. And that brings us
to a definition of quality I like best.
"Quality is conformance to
customer expectations"
That is all. The product may
be excellent but if it not according to the expectations of the customer you
still have a problem. Specifications (and they can be numerous) are just tools
to
comply
to the expectations of the customers. Also a certain life time belongs to these
expectations, depending on the product and the customer. If a car breaks down
within 10 thousand km then the customer complains, but if it concerns a walking
shoe no complaints are heard.
To
clear up the differences between quality and reliability Relia-Easy agrees with
other specialists who simply state:
Quality is everything until put into operation (0-hours)
Reliability is everything happening after 0-hours
Quality is today.
Reliability is the future. Quality is measurable and controllable. Reliability
is
crystal ball magic. The only problem is to define the exact moment of 0 hours.
This depends strongly on the logistics around the creation of a product. Think
about suppliers, sub modules etc. The product can be stored in a shop for a
long period before it is sold. Spare parts can be on stock for years before
they are used. The more complex the product the vaguer the 0 hour point. But
that is only a technical detail.
Quality is important. Even
more important is that this quality should be reproducible. Black belts and six
sigma projects play an important role in this area. A lot of literature is
available.
Reliability
is everything in the future. Crystal ball magic. It is the ultimate challenge
to forecast a 5 year life period within 3 months. Within certain limits and
with the right tools this is possible. But it requires a different approach and
discipline as in use with quality . In line with the definition for quality
reliability is best described as:
"Reliability is quality over
time"
Unfortunately a lot of
companies focus on the quality aspects until 0-hours and during itsdevelopment
barely attention is given to the reliability. Reliability is an essential part
of the
overall
quality but different in approach. Therefore Relia-Easy treats them as two
different
disciplines.
Many
companies have a Q&R department, a short for Quality and Reliability department.
The R
part is often questionable. It is confusing if companies defines Q&R as
Quality and
Regularity.
Reliability has completely disappeared. Or is it part of Quality?
No comments:
Post a Comment