Mental budgeting versus marginal decision making: training,experience and justification effects on decisions involving sunk costs

Many studies have shown that individuals make economically irrational decisions by using, rather than ignoring, sunk cost information. In this study, the effects of relevant academic training, financial experience and decision justification on investment decisions involving sunk costs were examined. Data on both the process (strategy) and outcome of the decisions were collected. The results indicate that practicing Certified Public Accountants (CPAs), Masters of Business Administration students (MBAs) and undergraduate accounting students perform better than undergraduate psychology students. The level of training, as measured by the number of college courses in managerial accounting, was found to be positively correlated with performance, while the level of experience, as measured by years of financially‐related work, was not. Justification was found to improve decisions only for those participants with significant work experience (MBAs and CPAs). Strategies used in this type of decision were examined with the surprising finding that economically rational decisions can be made even if sunk costs are not ignored. Copyright © 2007 John Wiley & Sons, Ltd.