Design verification and design validation are two distinct design controls. Both verification and validation requires a series of tests on a device to check against a certain set of inputs. However, the inputs tested in each of these categories differ. In short, verification tests check against the required specifications of a product, such as its required height, weight, or other characteristics specific to the design are met. On the other hand, validation tests check that the product is compliant with the customer needs that led to its development. For example, if you’re developing an exoskeleton, an important customer need is comfort. A validation test can check whether there is biocompatible padding on the device to prevent abrasions on the skin. It’s hard to determine which of the two types of tests are more important than the other since both check against what is required for the product. However, if I had to choose, I think that verification is a bit more important because these tests make sure that the product was manufactured correctly, thus preventing a faulty design. A faulty design may be a risk to those who use the product, and therefore, verification tests to ensure accurate measurements and development should be more emphasized. According to the list Dr. Simon provided in this week’s lecture, verification and validation tests should occur fairly close to each other, if not together. What are some other examples of verification and/or validation tests?

After listening to Dr. Simon's lectures this week I can think back and point to a time where I performed validation and verification tests. Last year in my senior capstone class we had to perform both verification tests to ensure our product met design specification and validation test to confirm that we met the customer and user needs. Examples of verification tests included measuring the physical requirement of the different parts of our device. To perform these verification tests we used calipers for smaller measurements and a tape measure for the larger measurements. When meeting these specifications, we made sure that each measurement recorded was with-in the given tolerances stated in our design specifications. As stated in this weeks lectures, tolerances are an important part of design verifications to ensure the product is made correctly. Since our product was only a rough prototype, there were instances when a measurement fell outside of the specified tolerance and we were able to change the spec of our design. Next were our validation tests which included functionality of our product and its ability to meet the users needs. Despite the prior post, validation testing seemed more important than or verification testing. Functionally we needed our device to move up and down through motorized controls and be able to hold a maximum load. Because we were in the early stages of a crash course on product development, by the end of the academic year the functionality of the device and its ability to perform specified tasks was most important. This may have been due to the construct of the class rather than real world applications, but for this specific project validation was more important than verification testing.

Design verification involves confirming that the design output meets the design input requirements (i.e. dimensions). Design validation ensures that devices conform to defined user needs (i.e. portable) and includes risk analysis as well as testing of units under actual or simulated use conditions. Therefore, both verification and validation involve constructing test plans which should be documented as part of the Design History File, however, verification and validation as described, occur at different stages of the development process. Design verification takes place as the product is being developed to ensure that the components meet design specifications, whereas design validation occurs once all components are brought together and you have a completed product that needs to be tested based on its intended use. 

Design validation is to prove the device's intended use, and design verification is to design inputs and outputs match.
According to the FDA, Design validation is establishing by objective evidence that device specifications conform with user needs and intended use.
According to the FDA, Design verification is confirmation by examining and providing objective evidence that specified requirements have been fulfilled.
Design Validation considers patient needs, but design verification is purely based on the design input process and output.

I recall for my senior capstone project we had to do verification and validation testing on our device and I had difficulty understanding what differentiated the two types of testing. Essentially, verification tests the specifications for the product, such as size, materials, and shape. On the other hand validation tests that the device actually meets the patient needs and accomplishes the original objectives. The way my professor explained it to me was that verification ensures that you "built the device correctly" and validation ensures you "build the correct device". Just meeting specifications does not mean that the device will function as it was intended to, thus validation testing is required to make sure it is "the correct device". 

Design verification is in the check phase, so this is where one makes sure the outputs equal the inputs. One way to ensure the verification phase is completed correctly is to create tests for the product and see how well it passes. If the product does not pass the test, one should change, alter the product and redo the test to make sure everything is within standards. In comparison, design validation checks to see if the input is equal to the user's needs. One validates a product by creating tests and seeing how it does after it is tested. However, validation is not always needed; for example, if there is no clinical trial or no product changes after verification, then validation is unnecessary. I believe verification is more important than validation because sometimes validation is not required, and verification is when you check to see if everything is correctly done as stated in the initial phases. 

Verification is checking that the device meets the specifications meant for the specific needs. For example, that the device has the correct measurements in the correct tolerances as well making sure that each input has a passing output. Validation is checking that the device works as it needs and completes the needed functions. Both verification and validation are very similar in aspect but they deal with slightly different parts of the device. And deciding which one holds more importance, I believe that it would be verification because there are instances where validation is not necessarily needed but verification is always needed. It also seems more important to ensure that the device is up to par and everything is built how it should be, ensuring that this test is done correctly it would be easier to go through validation. This leads to verification holding some more importance than validation.

It can be easy to confuse the two, verification and validation as they are extremely similar but they do have their own nuances to them. Design verification and validation can occur synonymously as they both involve product testing. In our capstone team, we were required to draft a test plan document with testing literature that described exactly how our team tested our product to ensure that we built a functioning and sound device. In that document verification and validation occurred through the various tests that we conducted. Verification is associated with tests that verifies dimensions and physical attributes of the product. For example, verification tests would assess whether the device was built within the given machining tolerances. Furthermore, if the device was meant to be waterproof that would be tested under verification as well. Validation focuses more on the customer and whether the device fits the customer's needs. While verification focuses more on the physical aspects of the product, the validation focuses on the usability and applicability of the device for the customer. When building a device, the engineers are responsible for integrating a base level device or product with specific requirements that are given by the customer and building a product that incorporates both aspects into one. For example, a customer requires you to create a scalpel, but the scalpel needs to be adjustable for different procedures and each procedure requires a different type of scalpel. The base device would be the scalpel but the customer needs for the scalpel would be to be an elevated that scalpel that can be readjusted for different procedures. So in this scenario, verification tests would make sure that scalpel is sharp enough to cut skin, and matches the proposed dimensions to the design, and validation tests would be responsible for testing whether the scalpel is adjustable and can be effectively used in varying procedures based upon the surgeon's needs. 

Design verification and validation are some of the last steps of the design control process. Design verification checks that the inputs outlined in the design input document match the outputs Verification involves creating and conducting tests for each output and forming a verification protocol document in accordance to the design specification document. Following design verification is design validation which checks that the inputs equal the user needs or intended use. Validation is not required for all products such as components of products, if a clinical trial is not needed, or if the product requires no changes after verification or if it requires changes, they do not affect the user interface. Validation involves people using the product to determine if it is to their satisfaction.  Both controls run tests on the inputs, but weigh the outcomes differently verification focuses more quantitative results while validation focuses more qualitative results. One is not more important than the other and both are equally important in the design control process as the product needs to be constructed with not just the right specifications, but must also be needed. 

Design verification and design validation both provide a power of checks and balance within design control. Design verification ensure all inputs have a respected output within the design of a medical device. While design validation ensures the inventor or team doesn’t not stray from their target population of goal. Making sure the medical device actually solves the problem it was intended to solve. I believe design validation is more important because it replies on meeting the needs of your target population in a safe way. If you can not do that, then you can not sell your product. 

Both design validation and verification serve as the vital steps in the medical device development since they maintain both product quality and regulatory compliance. Regulations such as, FDA QSR and ISO 13485 involve them, and they need detailed records showing that the design plans and acceptance criteria are being met.

They are two interrelated yet distinct tasks in medical device development. Validation ensures if the device is constructed according to the specifications, meets user needs and performs its intended role. In the development phase, validation is conducted towards the end and focuses real-world performance, while verification is completed earlier and focuses on technical reliability. Though validation often involves user testing and clinical trials, verification attempts may include inspections and analysis.

Neither is fundamentally more significant than the other. Both are essential to ensure the efficacy, safety, and market value of devices. Neglecting one or the other could end up in non-compliance, low performance, or threats to patient safety. 

The design verification is carried out during the early design process to verify if the end result fulfills input standards. Design validation is performed later, on near-final prototypes to validate the device's functionality and its intended use.