"What does it mean when a product meets specifications but fails in customer use?"
You must understand customer needs. The problem is that customers typically give specifications, not needs. For example, an automotive customer typically demands these things from the vendor:
Performance level or specifications
Features or functions
Specific hardware or methods
Complaint solutions or failure mode prevention
Lower prices, etc.
The voiced product performance, features, and methods may seem exciting in concept, but sometimes satisfying these requirements still fails to satisfy the customer, especially the end customer (consumers). That is because
"the stated customer wants are only a starting point in design. What they said they want is the best guesstimate of what they think the producer could deliver." [Glenn Mazur]
The late Steve Jobs, Apple Computer's founder, echoed this challenge for high-tech products:
"customers can't anticipate what the technology can do. They won't ask for things that they think are impossible. . . It takes a long time to pull out of customers what they really want, and it takes a long time to pull out of technology what it can really give." [1989 Inc. Magazine interview]
In new product development (NPD), our goal is to create the future experience and value for them. To do that, a better understanding of 'true' customer needs must take place. And that requires smarts on the part of designers and planners.
The relationship between the customer needs and what customers tell you is similar to a fishbone diagram with needs representing the "head" or a desired effect, and the specifications, functions, components, materials, etc. representing the "bones" or causal factors.
Customers are experts in "heads" and producers are experts in "bones." When customers give your bones instead of heads, you get "bonehead specs" ☺ where the customer mistakenly thinks their stated specs will meet their unstated needs. Then. when the product is delivered, it fails to fit their use, and they scream.
Remember the warning of Henry Ford. If asked what they wanted, the customers in his time might have voiced such a requirement as "I want an eight-legged horse" — a perfect example of "bonehead specs." Ford's genius was translating the stated specs into unstated, true needs like travel faster, can carry heavy loads, can travel on bad roads or no roads.
QFD (Quality Function Deployment) is the quality method designed to address this problem. Its earliest tools were fishbone diagrams that were used to translate product requirements (specs, functions, components, materials, etc.) into true customer needs (product independent benefits).
Later, the simple fishbone analysis was replaced with a more comprehensive series of matrices, the first of which came to be called the "House of Quality," due to its various "rooms" or attached tables. This Classical QFD approach from the 1970s became the most published tool in English language books. However, over time, it has become sub-optimal for modern businesses, because its exhausting examination of relationships results in exhausted team members giving up.
The Modern QFD tool set has refined these fishbones by adding additional analyses to clarify, prioritize, and benchmark customer needs. In the above automotive industry example, Classical QFD using a 4-phase model and House of Quality matrix would lump all of the customer-stated requirements together and attempt to prioritize the results. When you approach NPD (new product development) that way, not surprisingly, price and complaint issues dominate and the newly developed product tends to be an updated version of existing ones.
In contrast, modern QFD tools can uncover 'unstated' needs, the unknown unknowns and identify 'true' customer needs that should be the foundation for highly competitive products. In essence, Modern QFD tools are strongest where you want to make a difference by widening the gap between merely meeting product specifications vs. satisfying the customer.
Starting your NPD project with Modern QFD offers these advantages:
With an eye on the true requirements, rather than having to complete the large resource-intensive Classic matrices, the project team can study more innovative methods that would better address "what the customer wants" as opposed to "what the customer says."
Early on in the project, modern QFD approach can help the team identify the need to incorporate other creative methods such as Kansei Engineering or TRIZ.
Deeper understanding of VOC with modern tools gives a more solid foundation for deploying a House of Quality (HoQ) correctly and effectively as well as any of the other 30 QFD matrices if they are indeed needed.
By starting with Modern QFD approach, you will be able to avoid the common errors that we see in many published examples and commercial software, such as jumping right into creating a HoQ matrix by copying the stated VOC (Voice of Customer) directly from the customer verbatims or relying on a triangle-shaped 'roof' of the HoQ matrix to select a solution technology (doing this actually limits your technology options).
Lastly, these Modern methods are now being written into the new ISO 16355. Learning them in our public courses can give you the edge.