What is Validated Learning?

Let first we try to understand what is validation , Validation means to test a new idea or plan on the basis of what we are thinking about and is it proved right according to what are thinking or assuming.
Now validated learning is a unit for measuring performance in Lean method. According to lean startup methodology learning is of no value if it is not validated. We gain validated learning by the help of Build-Measure-Learn loop.
We have some assumption on the basis of our vision, and now in order to gain validated learning we have to test those assumptions on real customers by building and providing our customers with a prototype which we call as minimal viable product and then measure the customer feed back against our metrics, that is it aligned with what we were thinking (Congratulations! We are on right track and have to persevere) or is it quite different than our assumptions (Again Congratulations! We have saved from wasting time building a product that is not value creating for customer) and have got validated learning that what we are thinking is not going to work that way we have to pivot our strategy)

Value Vs Waste:

Value is every product or feature that engage customer and proves to be useful.
While every effort (no matter how useful it seemed) that customer not find valuable or engagable, is supposed to be a waste.

How to avoid waste?

Now in order to avoid wasteful efforts we need to validate our each initial assumption empirically as soon as possible before going to develop a full featured product.
We can test our fundamental idea by developing a minimal viable product and then measuring customers feedback according to our metrics.