Weinberg's Law of Twins

Weinberg's Law of Twins states that most of the time, no matter how much effort one expends, no event of any great significance will result. Weinberg's Law of Twins Inverted states that occasionally—particularly when one isn't expecting it—a significant event occurs. Gerald Weinberg invented the law and described it in his book "The Secrets of Consulting" (1986), in which he explains the origin of its name.

Weinberg reported that, while riding a bus in New York City, he observed a mother with eight small children embark. She asked the driver the amount of the fare; he told her that the cost was thirty-five cents, but that children under the age of five could ride for free. When the woman deposited only thirty-five cents into the payment slot, the driver was incredulous. "Do you mean to tell me that all your children are under five years old?" The woman explained that she had four sets of twins. The driver replied, "Do you always have twins?" "No," said the woman, "most of the time we don't have any."

ources

Weinberg, Gerald M.. "The Secrets of Consulting: A Guide to Giving and Getting Advice Successfully". Dorset House Publishing Company, 1986. ISBN 0-932633-01-3