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.