Excesso de confiança

O excesso de confiança (em inglês, overconfidence) é um enviesamento que leva as pessoas a sobreestimar o seu conhecimento, a subestimar o risco, e a exagerar a sua capacidade de controlar os acontecimentos. O excesso de confiança está presente na forte maioria das pessoas, e é muito mais prevalecente do que a falta de confiança.

O excesso de confiança está particularmente presente na especulação e investimentos, uma tarefa difícil, precisamente o tipo de tarefa em que as pessoas mais exibem este enviesamento.

O excesso de confiança é maior Overconfidence is greatest when accuracy is near chance levels. Overconfidence diminishes as accuracy increases from 50 to 80 percent, and once accuracy exceeds 80 percent, people often become underconfident. In other words, the gap between accuracy and confidence is smallest when accuracy is around 80 percent, and it grows larger as accuracy departs from this level. Discrepancies between accuracy and confidence are not related to a decision maker's intelligence."

Overconfidence and anchoring definitely appear to be part of the explanation underlying post-earnings-announcement drift

There are two main implications of investor overconfidence. The first is that investors take bad bets because they fail to realize that they are at an informational disadvantage. The second is that they trade more frequently than is prudent, which leads to excessive trading volume

Em áreas como a finança, os homens tendem a ter maior excesso de confiança que as mulheres.

Uma manifestação do excesso de confiança pode ser observada na forma como as pessoas geralmente se classificam como sendo "acima da média" em muitas áreas. No entanto tendem a não se classificar como estando no decil superior.

Ver também

• Bolha

Referências

• BARBER, B.M. and T. ODEAN, 2001. Boys Will be Boys: Gender, Overconfidence, and Common Stock Investment. The Quarterly Journal of Economics.
• CAMERER, C.F. and D. LOVALLO, 2000. 23. Overconfidence and Excess Entry An Experimental Approach. Choices, Values, and Frames.
• OSKAMP, S., 1965. OVERCONFIDENCE IN CASE-STUDY JUDGMENTS. J Consult Psychol.
• JUSLIN, P., 1994. The overconfidence phenomenon as a consequence of informal experimenter-guided selection of almanac …. Organizational behavior and human decision processes(Print).
• KYLE, A.S. and F.A. WANG, 1997. Speculation Duopoly with Agreement to Disagree: Can Overconfidence Survive the Market Test?. The Journal of Finance.
• DANIEL, K., 1998. A theory of overconfidence, self-attribution, and security market under-and overreactions.
• DANIEL, K.D., D. HIRSHLEIFER and A. SUBRAHMANYAM, 2001. Overconfidence, Arbitrage, and Equilibrium Asset Pricing. The Journal of Finance.
• MALMENDIER, U. and G. TATE, 2005. CEO overconfidence and corporate investment. Journal of Finance.
• SCHEINKMAN, J.A. and W. XIONG, 2003. Overconfidence and Speculative Bubbles - all 27 versions . Journal of Political Economy.
• KLAYMAN, J., et al., 1999. Overconfidence: It Depends on How, What, and Whom You Ask. Organizational Behavior and Human Decision Processes.