Not all design inputs are necessarily related to some performance output. For some requirements such as color or force, there is an output that can be related to manufacturing or test related value. For some inputs such as ones based for end user validation such as "device works as intended" or "surgeon is able to manipulate instrument with ease", the validation of the device is binary which is either a yes or no. There is no output as there isn't a specific color, force, or rationale for the input that is chosen based on whim of the end user. 

All inputs have outputs, but I believe your confusion may be arising from the document name. There is an input document, an output document, and a design specification document (DSD). From my understanding, the input and output documents are the two parts that come together to form an additional document: the DSD. A company can omit the output document because the outputs are included in the DSD. It is a bit redundant to include each input and output twice, but I believe the DSD provides a convenience to the reader so that each variable is in one location.

I agree that although there isn’t a document that explicitly states a design output, it doesn’t mean that the design doesn’t have an output. The design input provides a general overview of what your product will look like and how it will function. The design specification gives the specifications of what exactly those inputs that the user or customer required—for example, the example that Dr. Simon has given was with the knob: red would be your input and a specific dye of red would be your specifications. There are also the design verifications that confirm that the output of your design meets whatever was stated in your design inputs. So, although there isn’t a specific design output document, your end product is being tested and documented to ensure they meet design input and specifications.  

You are correct in the sense that every input in the design control process should have an output. However, some companies do not and one of the reasons could be because of the simplistic nature of the medical device at hand. For instance, let's take a digital thermometer as an example. The DID for this device could be accuracy and user interface requirements but the DOD is simply a reiteration of the input requirements such as the quality control procedures used that were dependent on the input arguments. However, if a more complicated medical device was at hand, then a clear distinction between the input and output requirements would be expected. 

As a student delving into the realm of medical device development, I've come to appreciate the pivotal role played by Design Controls in guaranteeing the safety and effectiveness of these devices. Design Controls encompass a meticulously structured set of procedures that guide the design process, from initial planning to manufacturing transfer. These activities encompass understanding user needs, regulatory requirements, gathering crucial design information, creating detailed designs, ensuring compliance through reviews, testing for verification, validating in real-world scenarios, and ensuring a smooth transition to manufacturing. The significance of Design Controls is manifold. They act as safeguards, identifying and mitigating potential design risks, preventing the introduction of medical devices that might pose safety or effectiveness concerns to patients. Furthermore, they serve as a cornerstone for regulatory compliance, with agencies like the FDA stipulating their implementation, enabling manufacturers to navigate the complex regulatory landscape. Importantly, they contribute to improving product quality, as they systematically guide the design and testing process, facilitating the early detection and rectification of design flaws, ultimately resulting in elevated product quality and cost savings. In summary, Design Controls are an indispensable facet of the medical device development journey, providing a structured framework for managing the design process, ensuring both safety and regulatory adherence, and serving as a fundamental knowledge base for students venturing into this field.