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Forecasting Errors Increase in Complex Environments

(p. 54) There is a great deal of evidence that suggests that when people-- for example, investors and managers--are taken out of a familiar environment--an environment of continuity--their ability to deal with the future deteriorates rapidly. John Sterman, J. Spencer Standish professor of management and director of the System Dynamics Group of MIT, who has studied the ability of managers to learn over long periods of time, says that in complex environments, the more experience people have the more poorly they perform. Here is a distillation of Sterman's findings:

• "Even in perfectly functioning markets, modest levels of complexity cause large and systematic deviations from rational behavior."
• "There is little evidence of adaptation of one's 'rules' as the complexity of the task increases." When the environment is complex, people seem to revert to simple rules that ignore time delays and feedback, leading to lowered performance.
• Individuals "forecast by averaging past values and extrapolating past trends. [They] actually spend less time making their decisions in the complex markets than in the simple ones."
• The lowered performance people exhibit as a result of greater com-(p. 55)plexity does not improve with experience. People become "less responsive to critical variables and more vulnerable to forecasting errors--their learning hurts their ability to perform well in the complex conditions."
• Most individuals do not learn how to improve their performance in complex conditions. In relatively simple conditions--without time delays or feedback--people "dramatically outperform the 'do nothing' rule, but in complex situations many people are bested by the 'do nothing' rule." Attempts individuals make to control the system are counterproductive.

Markets that are undergoing rapid or discontinuous change are extremely complex. Economic systems are highly networked and involve substantial feedback. Given Professor Sterman's findings, it is not surprising that forecasting deteriorates in the face of rapid change.


Foster, Richard N., and Sarah Kaplan. Creative Destruction: Why Companies That Are Built to Last Underperform the Market---and How to Successfully Transform Them. New York: Currency Books, 2001.

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