Behavioral Finance: Key Concepts - Gambler's Fallacy
  1. Behavioral Finance: Introduction
  2. Behavioral Finance: Background
  3. Behavioral Finance: Anomalies
  4. Behavioral Finance: Key Concepts - Anchoring
  5. Behavioral Finance: Key Concepts - Mental Accounting
  6. Behavioral Finance: Key Concepts - Confirmation and Hindsight Bias
  7. Behavioral Finance: Key Concepts - Gambler's Fallacy
  8. Behavioral Finance: Key Concepts - Herd Behavior
  9. Behavioral Finance: Key Concepts - Overconfidence
  10. Behavioral Finance: Key Concepts - Overreaction and Availability Bias
  11. Behavioral Finance: Key Concepts - Prospect Theory
  12. Behavioral Finance: Conclusion

Behavioral Finance: Key Concepts - Gambler's Fallacy

By Albert Phung

Key Concept No. 4: Gambler's Fallacy
When it comes to probability, a lack of understanding can lead to incorrect assumptions and predictions about the onset of events. One of these incorrect assumptions is called the gambler's fallacy.

In the gambler's fallacy, an individual erroneously believes that the onset of a certain random event is less likely to happen following an event or a series of events. This line of thinking is incorrect because past events do not change the probability that certain events will occur in the future.

For example, consider a series of 20 coin flips that have all landed with the "heads" side up. Under the gambler's fallacy, a person might predict that the next coin flip is more likely to land with the "tails" side up. This line of thinking represents an inaccurate understanding of probability because the likelihood of a fair coin turning up heads is always 50%. Each coin flip is an independent event, which means that any and all previous flips have no bearing on future flips.

Another common example of the gambler's fallacy can be found with people's relationship with slot machines. We've all heard about people who situate themselves at a single machine for hours at a time. Most of these people believe that every losing pull will bring them that much closer to the jackpot. What these gamblers don't realize is that due to the way the machines are programmed, the odds of winning a jackpot from a slot machine are equal with every pull (just like flipping a coin), so it doesn't matter if you play with a machine that just hit the jackpot or one that hasn't recently paid out.

Gambler's Fallacy In Investing
It's not hard to imagine that under certain circumstances, investors or traders can easily fall prey to the gambler's fallacy. For example, some investors believe that they should liquidate a position after it has gone up in a series of subsequent trading sessions because they don't believe that the position is likely to continue going up. Conversely, other investors might hold on to a stock that has fallen in multiple sessions because they view further declines as "improbable". Just because a stock has gone up on six consecutive trading sessions does not mean that it is less likely to go up on during the next session.

Avoiding Gambler's Fallacy
It's important to understand that in the case of independent events, the odds of any specific outcome happening on the next chance remains the same regardless of what preceded it. With the amount of noise inherent in the stock market, the same logic applies: Buying a stock because you believe that the prolonged trend is likely to reverse at any second is irrational. Investors should instead base their decisions on fundamental and/or technical analysis before determining what will happen to a trend.

Behavioral Finance: Key Concepts - Herd Behavior

  1. Behavioral Finance: Introduction
  2. Behavioral Finance: Background
  3. Behavioral Finance: Anomalies
  4. Behavioral Finance: Key Concepts - Anchoring
  5. Behavioral Finance: Key Concepts - Mental Accounting
  6. Behavioral Finance: Key Concepts - Confirmation and Hindsight Bias
  7. Behavioral Finance: Key Concepts - Gambler's Fallacy
  8. Behavioral Finance: Key Concepts - Herd Behavior
  9. Behavioral Finance: Key Concepts - Overconfidence
  10. Behavioral Finance: Key Concepts - Overreaction and Availability Bias
  11. Behavioral Finance: Key Concepts - Prospect Theory
  12. Behavioral Finance: Conclusion
RELATED TERMS
  1. Tight Monetary Policy

    A course of action undertaken by the Federal Reserve to constrict ...
  2. Laissez Faire

    An economic theory from the 18th century that is strongly opposed ...
  3. Sortino Ratio

    A modification of the Sharpe ratio that differentiates harmful ...
  4. IRR Rule

    A measure for evaluating whether to proceed with a project or ...
  5. Climate Finance

    Climate finance is a finance channel by which developed economies ...
  6. Financial Modeling

    The process by which a firm constructs a financial representation ...
RELATED FAQS
  1. What are the primary assumptions of Efficient Market Hypothesis?

    The primary assumptions of the efficient market hypothesis (EMH) are that information is universally shared and that stock ... Read Full Answer >>
  2. When does a growth stock turn into a value opportunity?

    A growth stock turns into a value opportunity when it trades at a reasonable multiple of the company's earnings per share ... Read Full Answer >>
  3. What is finance?

    "Finance" is a broad term that describes two related activities: the study of how money is managed and the actual process ... Read Full Answer >>
  4. What is the 'Rule of 72'?

    The 'Rule of 72' is a simplified way to determine how long an investment will take to double, given a fixed annual rate of ... Read Full Answer >>
  5. What is the formula for calculating EBITDA?

    When analyzing financial fitness, corporate accountants and investors alike closely examine a company's financial statements ... Read Full Answer >>
  6. How do I calculate the P/E ratio of a company?

    The price-earnings ratio (P/E ratio) is a valuation measure that compares the level of stock prices to the level of corporate ... Read Full Answer >>
Hot Definitions
  1. Inverted Yield Curve

    An interest rate environment in which long-term debt instruments have a lower yield than short-term debt instruments of the ...
  2. Socially Responsible Investment - SRI

    An investment that is considered socially responsible because of the nature of the business the company conducts. Common ...
  3. Presidential Election Cycle (Theory)

    A theory developed by Yale Hirsch that states that U.S. stock markets are weakest in the year following the election of a ...
  4. Super Bowl Indicator

    An indicator based on the belief that a Super Bowl win for a team from the old AFL (AFC division) foretells a decline in ...
  5. Flight To Quality

    The action of investors moving their capital away from riskier investments to the safest possible investment vehicles. This ...
Trading Center