Information asymmetry means that the parties in the interaction have different information, e.g. one party has more or better information than the other. Expecting the other side to have better information can lead to a change in behavior. The less informed party may try to prevent the other from taking advantage of him. This change in behavior may cause inefficiency. Examples of this problem are
selection (adverse or advantageous) and
moral hazard. Adverse selection occurs when one side of the partnership has information the other does not and this can occur deliberately or by accident due to poor communication. A classic paper on adverse selection is
George Akerlof's
The Market for Lemons. The most common example of the Lemons Market is in the automobile industry. As suggested by
Akerlof, there are four car types that a buyer could consider. This same dilemma exists in a multitude of markets where sellers have an incentive to not disclose information about their product if it is poor quality due to knowledge that the average standard across the industry from good products existing will boost their selling power. This is due to two reasons. Firstly, uncertainty between the buyers and sellers and secondly in the broader market where only sellers with below average vehicles will be willing to sell due to the reduced quality being represented. For example, if someone purchased car insurance for their vehicle and afterwards held their responsibility to a lower standard by going over the speed limit for example or generally driving recklessly. The
2008 financial crisis is another example, where
Mortgage-backed securities were formed through the collation of subprime mortgages and sold to investors without disclosing the risk involved. For moral hazard, contracting between
principal and agent may be describable as a
second best solution where payoffs alone are observable with information asymmetry. Insurance covers will often include a waiting period clause to refrain agents from changing their attitude.
Signaling Michael Spence originally proposed the idea of
signaling. He proposed that in a situation with information asymmetry, it is possible for people to signal their type, thus credibly transferring information to the other party and resolving the asymmetry. This idea was originally studied in the context of looking for a job. An employer is interested in hiring a new employee who is skilled in learning. Of course, all prospective employees will claim to be skilled at learning, but only they know if they really are. This is an information asymmetry. Spence proposed that going to college can function as a credible signal of an ability to learn. Assuming that people who are skilled in learning can finish college more easily than people who are unskilled, then by attending college the skilled people signal their skill to prospective employers. This is true even if they didn't learn anything in school, and school was there solely as a signal. This works because the action they took (going to school) was easier for people who possessed the skill that they were trying to signal (a capacity for learning).
Screening Joseph E. Stiglitz pioneered the theory of
screening. In this way the underinformed party can induce the other party to reveal their information. They can provide a menu of choices in such a way that the optimal choice of the other party depends on their private information. By making a particular choice, the other party reveals that he has information that makes that choice optimal. For example, an amusement park wants to sell more expensive tickets to customers who value their time more and money more than other customers. Asking customers their willingness to pay will not work - everyone will claim to have low willingness to pay. But the park can offer a menu of priority and regular tickets, where priority allows skipping the line at rides and is more expensive. This will induce the customers with a higher value of time to buy the priority ticket and thereby reveal their type. ==Risk and uncertainty of information==