In our day-to-day usage, we do use Validation and Verification interchangeably. Infact, depending on the industry you work in, it could be totally fine to use these terms interchangeably or it could be totally disastrous!
From Project Management perspective, these two terms carry quite a different meaning.
Validation is related to the Validate Scope process. Obtaining client’s or key stakeholders’ formal acceptance on deliverables is precisely validation.
Verification, on the other hand, means evaluation of whether requirements, regulations, specifications or imposed conditions are being met.
In order to understand this better, let’s take up an example of a software project. Once a feature is ready, the testing team performs testing which is basically verification. Once the testing is complete, the feature can be presented to the client to seek formal approval which, as you already know, is validation (or performing the validate scope process).
Certain texts do define Verification being internal while Validation being external, although that might not be true at all times.
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