A group of engineers and a group of economists ride the train togetherto a conference. Every business administrator has a ticket, but the whole group of engineers has only one ticket. Suddenly, one of the engineers calls out, “The conductor is coming!”, Whereupon all the engineers squeeze into one of the toilets. The conductor inspects the business administrator, sees that the WC is occupied and knocks on the door: “The ticket please!” One of the engineers pushes the ticket under the door and the conductor withdraws satisfied. On the return trip, the business economists decide to apply the same trick and buy only one ticket for the whole group. They are very surprised when they realize that the engineers have no ticket at all this time. Again one of the engineers calls: “The conductor is coming!” Immediately the economists drop into the one WC, The engineers make their way to the other WC a bit more leisurely. Before the last of the engineers enters the bathroom, he knocks on the business economists: “The tickets please!” And the moral of the story? Business economists should not use engineering methods that they do not really understand.