This article fascinates me. The author presents what he himself describes as a “five point star”, then asks people how many points there are. The most common answer is not five!
For the most common answer to be 10, there must have been some other context, perhaps implicit in the presentation leading up to the question, or in the selection of people to ask. Unfortunately, this detail is not very obvious in the article.
Still a very interesting point about communication of requirements, though!