Sterman (1989) also argued that the bullwhip effect is caused by the irrational decision making of participants.
After examining the results of the well-known role-playing game, the beer distribution game, he concluded that the participants of the game underestimated the ordering delays and, more importantly, that they did not take the entire supply chain inventory into account in placing orders.
The poor decision was deemed to come from difficulties in evaluating complex feedback loops in conjunction with time delays.