[Oblarg]

Originally Posted by Boltman

..and from a statistical perspective not enough sample size either.

This is a big part of what constitutes "garbage in," yes.

Along these lines, there are some very interesting cognitive science results that suggest that people make better judgments with extremely limited data sets when they rely on heuristics and intuition rather than explicit utility calculations. This is unsurprising, as the act of formalizing one's reasoning in that way often greatly restricts the body of evidence that you're actually using (since you only end up taking into account those things which you explicitly quantify), even if you're not aware of it. While in situations where you have large amounts of data this drawback is hugely outweighed by the benefits, when you're stuck with little information to begin with it can (and does) do more harm than good.