Prediction Markets.pdf

Here is a detailed but concise summary of the article "Prediction Markets for Business and Public Policy" by Andrew Leigh and Justin Wolfers:

Introduction: Prediction markets have gained significant attention among social scientists, policymakers, and the business community due to their recent successes in predicting public events and corporate outcomes.

What are Prediction Markets?: Prediction markets are platforms where participants trade contracts whose payoff depends on unknown future events. The price of these contracts can be directly interpreted as a market-generated forecast of some unknown quantity.

Examples: The Iowa Electronic Market, Google's internal prediction market, and online platforms such as Tradesports.com and Betfair.com are examples of prediction markets. These markets have been used to predict election outcomes, economic statistics, and other events.

Key Features: Prediction markets have several key features, including:

1. Efficient Markets Hypothesis: The price of contracts reflects all available information, making them efficient and unbiased forecasts.
2. Information Aggregation: Prediction markets aggregate information from multiple sources, making them more accurate than individual forecasts.
3. Rational Traders: While not all participants need to be rational, the marginal trade in the market is motivated by rational traders.

Accuracy: Research has shown that prediction markets can be more accurate than traditional forecasting methods, such as opinion polls. For example, the Iowa Electronic Market has been more accurate than opinion polls in predicting US presidential election outcomes.

Design and Constraints: The article discusses the importance of designing effective prediction markets and the constraints of the current legal regime.

Conclusion: Prediction markets have the potential to provide efficient and unbiased forecasts, making them a valuable tool for businesses and policymakers. The article concludes by highlighting the growing interest in prediction markets and their potential applications in various fields.