How do you use design verification and validation to ensure product performance and customer satisfaction?

Often, the methods and acceptance criteria for verification testing represent in vitro conditions and are specified in relevant standards.

Rationale is an important piece from sample size (which should be risk based), how samples are to be created/ collected, to test set - up (are appropriate ranges covered etc, as well as considerations for worst case (not that they have to be tested). It is a crucial piece often missing from verification, if compliance to a standard is not being leveraged.

First, you need to understand Design Inputs and Outputs. Design Inputs include: - Functional Specifications, derived from User Needs. - Technical Specifications, derived from Functional Specifications. Functional Specifications define what the device needs to do, while Technical Specifications explain how to implement those functions. The product produced from these Design Inputs is called the Design Output. Design Verification involves creating objective evidence—through bench testing, simulation, or inspection—that the Design Output matches the Design Input. Essentially, you verify that your product works as planned, both technically and functionally. Once verified, you ensure it meets User Needs through Design Validation.

Design Validation involves providing objective evidence that the product design satisfies user needs. In my opinion, the term "user needs" is an oversimplified concept. The correct term should be "stakeholders' needs." I work in the medical device industry, where user needs encompass not only patient needs and operators' needs, but also regulatory needs and other relevant stakeholders requirements that must be addressed within the product design. Performing validation consists to take the list of user needs you have documented before starting the product design and using methods (such as clinical trials, usability testing, regulatory gap assessments, or real-world testing) to prove that your product fulfills stakeholders' requirements.

This is missing the most important piece, which is ensuring the outputs are safe and effective. Medical devices are used on the most vulnerable in society and they should be able to trust they will do what they say and not make things worse.

Without mentioning the obligation to perform verification and validation for market approval within regulated industries, consider this: If you do not validate your product, you may put something on the market that no one can or wants to use. If you do not verify your product, it may simply not function, making it impossible to validate. In any case, if you do not perform V&V, you risk spending millions, or even hundreds of millions of USD, to fully redesign a product. Even worse, you may put a large number of lives at risk, as verification and Validation play a huge part in ensuring that the Risk Control Measures are implemented and efficients.

An additional requirement for robust verification and validation is predetermined pass/fail criteria including the statistical methods or standards to be used.

First, segregate verification and validation. A product that is not verified is considered unreliable and unsafe, and therefore unfit for validation. Your overall strategy should be to group your specifications by themes that can be easily tested together. You can organize them by function, subsystem, or whatever is most relevant to your product or testing resources. Then, define your test cases. Test cases describe how you will verify your specifications. Each test case contains the test environment, conditions, materials to use, and the design inputs it verifies. Additionally, it includes a list of test steps with the expected results for passing. You can group test cases into thematic test sets as appropriate.

Performing feasibility testing on all planned tests prior to executing design verification is a great way to minimize risk of failures during DV and is worth the extra time and effort to ensure your processes are 100% solid.

Add have an easy to implement and understandable process for handling deviations as well as documentation and disposition of failures or unexpected observations.