Developing any new product, service or system requires that it be both verified and validated. Providing the necessary assurance can require considerable time, effort and infrastructure to enact and it is important that this is considered from the outset.
Validation is the assurance that the product, service or system meets the needs of the customer and other identified stakeholders. Verification, on the other hand, evaluates whether or not a product service or system complies with a regulation, requirement, specification or imposed condition. The former confirms that “the right product is being built” whilst the latter confirms that “it was built right”.
It is important to consider the needs of the verification and validation (V&V) process up front because there is often a need to develop special infrastructure (test harnesses, platforms and tools) in addition to securing access to other resources that may well be in high demand or require special training or other provision in order to utilize them. In my experience it is not unusual for the test arrangements to be as complicated as the system (or subsystem) under test so it can easily assume a large part of the overall scope and carry significant attendant risk.
It can be tempting to focus almost exclusively on solution development and defer examination of the V&V requirements until nearer their scheduled enactment. The trouble with this approach is that there may then be insufficient time to put the necessary resources in place. This could range from simply not having the right tools for the job (risk of damage, delay or even a safety incident) to not being able to access the test site due to visa, security or safety prerequisites.
An evolutionary (iterative and incremental) development process facilitates progressive accumulation of both verification and, importantly, validation information. This approach has been practiced for decades in the defence and aerospace industries and has experienced new-found interest in Agile, Test-Driven Development and Lean-Startup methodologies.
Careful consideration should be given to the V&V approach for each requirement, feature or user story. Assurance methods range from pure analysis (incl. simulation and analogy), through intermediate lab or workshop testing of prototypes all the way up to operational demonstrations or pilot runs in the end-user environment.
As I stated in the title, the key point here is to start with the end in mind and not leave it all to the last minute.