3. Sources of factual information

Every laboratory or design office has a certain number of books and an address book from which most of the necessary information can be obtained. The habit of these privileged consultations can give rise to an excess of confidence in the data collected, leaving the user at a loss when faced with an unanswered question.

Pressed by the need to obtain the data they are looking for, users adopt an irrational and often costly approach if they have not made as exhaustive an inventory as possible of their potential sources of information. This inventory must therefore be drawn up, completed, kept up to date and, preferably, evaluated, independently of any specific problem. This paragraph suggests a number of avenues that should be systematically explored.