How do we validate our persona?

When we pursue our goal of ease of use for our users we sometimes use personas to test or guide our designs. And that’s all good – because it gives us a feeling of how a user would interpret the design based on her prerequisites. And we find the design to suit the different persona we use in our daily work, and we move along in the belief that everything is fine and dandy.

But in terms of quality, we cannot really be sure that our persona really works unless we validate them. And that’s the question here: How do we validate our persona?