What is quality? What does it mean to you? What is it good for? Why is it so overhyped these days?
Reasonably many questions come up related to the word "Quality", as it surrounds us in our everyday life in every time, in every place. Each product, item, raw material,
service has a level of quality and this level can be numbered in some ways. And in some ways NOT. This is the reason why everything has an objective and subjective quality level.
Let’s define quality from two aspects. The first aspect is the World of facts, figures, data, numbers, and specifications. Having known these numbers of a product or service,
we can clearly compare it with one another. From now on we will call it objective quality.
The other aspect of quality is subjective. It represents the latent or implied needs of the customer that means different and subjective requirements. These expectations
are not specified, everyone weights them differently.
Many quality definitions refer to either one or both aspects, and all are right. Some examples:
- Quality is the grade of excellence, that meets or even exceeds customer expectations (both objective and subjective).
- Quality means the fulfillment of both stated and latent expectations (both objective and subjective).
- Quality is how a product or service fills its function (rather objective).
- Quality means conformance to requirements (rather objective).
- Quality is the state of being free from defects (both objective and subjective).
To understand the meaning of quality, we have to analyze both objective and subjective functions of products and services. On top of that, quality evaluation depends on the
roles in the supply chain, whether we are the customer or the manufacturers / providers. The next section helps to identify the key aspects, and to make quality transparent.
Objective quality is measurable, determinable and can be described with statistics or key performance indicators (KPI). The evaluation of product / service quality is based
on documentation, by measuring its physical and functional characteristics and comparing them to the predefined specification. In everyday life, this defines what a failure is and what is not (also gives the
basis for acceptance / rejection of claims).
The specification of a metal shaft prescribes 120 + / - 0.5 mm. The length of the inspected part is 120.8 mm, so the part is longer, than the allowed maximum length. This
is a measurable and determinable discrepancy.
Let’s compare two different cars from different manufacturers. The basis of the comparison will be a commonly used KPI: the number of failures at the end-user (field failures).
The KPI is calculated in parts per million (ppm).
The end-user failure KPI of Model A is 300 ppm, while the same KPI of Model B is 600 ppm. This means, that the quality level - from functionality point of view – of Model B is
worse, since twice as much failures are registered compared to Model A.
To compare two products objectively, it is essential to have the same attributes. As shown in the example, both products are cars, and both can have functional failures (e.g.
the product does not operate or breaks down).
Subjective quality is not measurable, as it is not specified, and represents the latent needs of the customer, the "feeling of quality" and all the intangible characteristics.
Subjective attributes of a product are not measurable, still statistics can be created (e.g. the furniture producer makes a survey about the comfort of its latest sofa model).
The client is about to buy a new laptop. Both models have the same technical specification (size, weight, processor speed, amount of memory, warranty time, etc.), but she
finds Model A more attractive, as it is white, and its special finish provides better feeling at a touch. The sense made her to choose Model A instead of Model B, so she was making her decision based on
subjective quality, in this case aesthetics and feelings.
History has proven, that the most successful and best-selling products were not designed and made only by considering technical characteristics and manufacturability, but
aesthetics, feeling, ergonomics, and all other subjective attributes always did matter.
The next table shows examples from every-day life about objective and subjective quality:
|Objective and subjective quality
|"The display of my smart phone went wrong in 3 months. My previous phones were better, as I could use them for 3 years each without any functional failure" – End user
||"The quality of leather bags is better, than the bags made of leatherette" – End-user
|"I’m satisfied with my actual internet provider. Their uptime is 99.9%, while my previous provider sustained only 98.5%" - Client
||"I’m satisfied with my internet provider. They are fast, reliable, and the help desk is always kind and accurate" – Client
|"It was a good decision to replace some of our old machines. Our reject rate at the final test gate dropped from 5.2% to 2.4% in one month" - Manufacturer
||"I think car brand A is better, than B, because their value added service is exceptional" - Client
|"We will choose our well-tried supplier again during the tender, as their quality is outstanding. They were supplying us parts during the last 4 years under 30 ppm" - Manufacturer
||"When I sit into this model, the feeling of quality is exceptional and much better compared to any other models" - Client
|"We have to improve our quality. This is the 3rd incident this year, and our external cost of quality reached 300,000 USD" - Supplier
To supply products or to provide services that meet customer expectations, all phases of the product realization process must be covered:
- Engineering / design: design of quality, consideration of risks, manufacturability, production technology, function, aesthetics, ergonomics, user experience.
- Purchasing / procurement: selection of suppliers, supplied materials and services.
- Manufacturing / production: manufacturing machines, production technology, and production processes.
- Customer: relevant services, help desk, warranty, communication, sales activities and promotion.
Do not forget that as product complexity increases, so does the difficulty to manufacture it in the right way, and that increases the chance of failures (risk). Only robust
design can ensure the high level of quality, and proper manufacturability, leaving nothing to chance. In order to reach that, the product- and process design phases are the most crucial points. That’s the reason
why the method of Advanced Product Quality Planning (APQP)
has been developed and established in the past. Use it, and not just in the automotive