Yes. I'm also familiar with the extent to which, when it comes to border security, for example, unless you have catastrophic failure, you tend not to be aware of whether something is effective or not. So, for example, if someone crosses the border, comes into the country, leaves again, and actually doesn't do anything, we have no way of knowing whether in fact that individual was a risky individual. Just because they chose not to act, we're unaware and may falsely put it down as demonstrating effectiveness.
On October 3rd, 2012. See this statement in context.