We never ask candidates to demonstrate their skill. We ask lots of questions about past experience, but simply looking at the results of their decisions does not let us understand the process that they used to make the choice in the first place. A good analogy is sports. If you wanted to know how well a person plays basketball, for example, you could look at statistics like shooting percentage or blocked shots. But, this is just an historical account of how well the individual played in the past - the numbers do not tell us much about how that individual plays basketball now.