Design Verification and Design Validation are key requirements in ISO 9001:2015, and often confused as one activity or confused with one another. However, these are distinct steps, and each one is important to ensure that the design is meeting the requirements of the customer. Design verification ensures that you have incorporated all the requirements set out for the product or service in the design, and design validation ensures that the design that is finally produced will meet the customer requirement.
This article will further explain the key differences between design verification and design validation, and will guide you on how to implement these in your operational processes.
Design Verification
The objective of the design verification activity is to confirm if the design outputs are meeting the design inputs or not. Typical design verification activities may include inspection, testing, comparing new design to previous design of a similar product, reviewing the design documents, analysis or measurements, etc.
Let’s take an example of a construction business to understand this better. For an architect working on the building, the customer requirements will serve as design input. He may also need to take care of regulatory requirements, some standards, codes, if any, while designing the building, which serves as additional design inputs. He also needs to ensure that the construction and maintenance of the building is feasible, and at the same time, the building is constructed at a low cost. The design output that he will create is a drawing that will incorporate all the design inputs. For him, it is important to verify if his design is right or not, and if it fulfills all the requirements or not. He needs to ensure that the design output, i.e the drawing, meets the design inputs. While reviewing his designs, he will verify that the design
- is traceable to design inputs
- meets all customer requirements
- is compliant with standards or codes
- is compliant with regulatory and statutory requirements
- is low-cost and value-for-money
- is constructible and maintainable
This review of the drawing against the design inputs is what is called Design Verification.
Another example for a air-ticket booking website, the developers may do various code reviews, unit testing, functional testing, system testing, etc. to verify that the website meets all the requirements defined by the customer.
It is important that the design verification activities are planned as the design matures. Design verification can occur at different phases of a design and development process. Elaborate inspection or test procedures should be written detailing out the pass/fail criteria to ensure that the verification is done effectively. An organization should establish that specified requirements have been fulfilled in the design through documented evidence. This could include test reports, inspection checklists or reports, design review and traceability records, etc.
Design Validation
The purpose of design validation is to check if user needs are met by the design. Through design validation, an organization checks the suitability of the product or service for its intended use. Various methods may be used for validation purposes, for example, trials or tests done in the end-user environment, process capability studies, etc.
Since validation is all about ensuring the intended purpose of the product/service is met, therefore it is important to specify as a design input:
- The environment and conditions under which the final product/service will operate
- the skills, knowledge and abilities of the end-users
- how the final product or service will be used, etc.
For the architect who has completed the design and verified the drawings through the steps we defined earlier, he now needs to check if the design of the building suits the intended purpose. For example, if the building is created for a hospital, he needs to ensure that the building has arrangement for nurse stations, easy access for disabled patients, enough space and arrangements for medical equipment, etc.
Similarly, a shopping mall will have an entirely different set of requirements and end-user needs which should be catered to. The architect will validate such points at different point of time during construction by conducting site inspections, and validating what is being built matches the design. He may also use inspection checklists to verify the design meets the end-user requirements.
An air ticket booking website may need to do performance or load testing to ensure that they will be able to take up multiple people logging for ticket bookings before they go live with the website. At times, companies also go for beta testing to check the performance of the finished product in real world scenario. This is a type of user acceptance testing.
Typical methods used for validation under different scenarios include user acceptance testing, usability testing, comparisons to similar products/service in the market, simulations, clinical trials, etc.
Any defects or issues found during the design verification and validation activities shall be resolved to closure before the organization proceeds with further production.
It is always recommended to establish acceptance criteria before validation tests start. This can be subjective or objective, as it fits your product/service that you are delivering. Another key thing to understand here is that final design validation always follows design verification activities; it never comes before it. As we have seen in our examples above, while design verification and design validation may have some overlapping attributes, they have different purposes. An easy way to differentiate between them is verification answers “Did we build the product or deliver the service right to meet the requirements? And validation answers the question “Did we build the right product or deliver the right service for the user?”
