From my experience, sir, here is an example of when that works really well.
I heard a case in which a young man said, “I carried a rucksack that weighed about 175 pounds”. I said to him, “Sir, with my experience, in the airborne, the heaviest I carried was between 100 and 125 pounds”. I asked him, “Did you actually weigh the rucksack?” He said, “No”. I said, “So, it's what you believe,” and he said, “Yes”.
I accepted that. It's what he believed. Another colleague may have said his testimony was not credible, but I was able to associate with him.