Non-scientists would be surprised how often this happens in science.  Take a really hard question and some scientist will do their best to come up with an estimate.  That part is fine.<p>The problem is when other scientists do literature searches, find the &quot;answer&quot; then base their entire work off of it.  Every scientist after that does the same thing and suddenly a wild-ass-guess becomes fact.<p>A great example is in epidemeology.  I work in biotech and many of our forecasts are based on epi data.  I remember one time when someone questioned a numbered, so our epi team did some work.  The number was the only estimate available, but it turned out to come from a paper from the 1700&#x27;s that looked at the prevalence of this disease in orphan children in some small Frech town.  We would have been better off just guessing.<p>This happens a <i>lot</i>.