In this post, I am going to explain the basics behind another common market failure, information asymmetry. If you would like a more broad overview of what a market failure is, I have a previous blog post on that topic. If you want more deep dives on market failures, check out my posts on the tragedy of the commons, externalities and natural monopolies. Additionally, I won’t be going into any of the math behind this concept. Instead, this will be a more intuitive discussion of how information asymmetries work and what their impact on markets is.
What is information asymmetry?
Information asymmetry occurs when one person in a market transaction has some hidden information that impacts the transaction. In an ideal market, all the information would be public so that buyers and sellers can accurately judge the value of the goods they are trading. Information asymmetries distort markets by undermining this condition.
A classic example of information asymmetry is in the used car market, where sellers often have significantly more information about the condition of a car than buyers do. If a car has hidden mechanical issues, the seller is unlikely to volunteer that information, while the buyer has limited ability to detect those problems before purchasing. Because of this uncertainty, buyers may be unwilling to pay a high price, even for cars that are actually in good condition. This specific example was made famous by the economist George Akerlof in his paper “The Market for Lemons”.
Why is information asymmetry a market failure?
Information asymmetry leads to market failure because it prevents markets from reaching efficient outcomes. In a well-functioning market, prices reflect the true value of goods based on accurate information. When one side of a transaction has better information than the other, prices instead reflect uncertainty and risk.
This often results in two related problems: adverse selection and moral hazard. Adverse selection occurs before a transaction takes place, when hidden information causes one side of the market to disproportionately attract lower-quality participants. In the used car example, buyers anticipating hidden defects lower the price they are willing to pay, which pushes out sellers of high-quality cars and leaves behind mostly lower-quality options.
Moral hazard occurs after a transaction takes place, when one party changes their behavior because they are not fully exposed to the consequences of their actions. For example, an individual might begin to drive more recklessly knowing they have a comprehensive car insurance plan. The insurance company doesn’t know that this person is going to change their behavior after the contract is signed (that’s the asymmetry) so they can’t properly account for that risk in the market transaction.
How policymakers respond to information asymmetry
Because information asymmetry can undermine markets, both private institutions and public policy often step in to reduce its effects. One common approach is to increase transparency by requiring disclosure of relevant information. For example, sellers may be required to report known defects, and companies may need to provide standardized financial statements so investors can make informed decisions.
Another approach is signaling, where the better-informed party takes steps to demonstrate quality. Warranties, certifications, and professional licenses all serve as signals that help build trust between buyers and sellers. For instance, a warranty on a used car gives buyers confidence that the seller stands behind the product.
Another example of signaling are reputation mechanisms like Uber’s rating system. Both drivers and passengers have their performance rated so both parties can get a better idea of how the transaction is going to go. These systems have been shown to be effective in reducing the impacts of information asymmetry.
Regulators can also play a role in setting minimum standards and protecting consumers. Laws around fraud, product safety, and truth in advertising all aim to reduce the most harmful effects of asymmetric information.
While information asymmetry cannot be eliminated entirely, these tools help markets function more effectively by narrowing the information gap. When buyers and sellers have better access to reliable information, they can make more informed decisions, leading to outcomes that are closer to what we would expect in an ideal market.