How do metrics tell you that a search query produces the result the user really wanted rather than fooling the user or forcing them to settle or even give up? A lot of my queries involve clicking a link and then realizing the site is garbage and just closing the tab.
So I submit a query, click a link, then I give up and close the tab. How do you tell that apart from me finding exactly what I wanted and staying there? Whether it's my first query or the 10th (and final) query in a chain of re-queries, you still have no way of knowing when I've found what I wanted or when I've given up.
