When your friend who lives in the UK tells you that her new telephone number is 020 7262 3395, you write it down. You expect to use the number many times in the future so, rather than just jotting it onto a scrap of paper, you record it in your address book, your computer, or your PDA. This friend lives in inner London, as do you, so when you call this friend, you dial all the digits in the number.

The aim of requirements reuse is to save time and effort and build better relationships by avoiding the duplication of work. Requirements reuse is the ability to benefit from requirements knowledge that has already been captured. This does not mean that all requirements knowledge must be formally defined in exactly the same way.

Daniel Kahneman, this year's co-Nobel prize winner in economics, and the late Amos Tversky extensively documented the difficulties individuals have in the realm of judgment under uncertainty and decisionmaking in the face of risk. On a regular basis, I run across corporate examples of Kahneman's and Tversky's descriptive theories on human behavior and judgment.

Daniel Kahneman, this year's co-Nobel prize winner in economics, and the late Amos Tversky extensively documented the difficulties individuals have in the realm of judgment under uncertainty and decisionmaking in the face of risk. On a regular basis, I run across corporate examples of Kahneman's and Tversky's descriptive theories on human behavior and judgment.