Стратегия выявления скрытой информации и борьба с неблагоприятным отбором.

Strategy of combating adverse selection
Screening in economics refers to a strategy of combating adverse selection – one of the potential decision making complications in cases of asymmetric information – by the agent(s) with less information. For the purposes of screening, asymmetric information cases assume two economic agents, with agents attempting to engage in some sort of transaction. There often exists a long term relationship between the two agents, though that qualifier is not necessary. Fundamentally, the strategy involved with screening comprises the “screener” (the agent with less information) attempting to gain further insight or knowledge into private information that the other economic agent possesses which is initially unknown to the screener before the transaction takes place. In gathering such information, the information asymmetry between the two agents is reduced, meaning that the screening agent can then make more informed decisions when partaking in the transaction. Industries that utilise screening are able to filter out useful information from false information in order to get a clearer picture of the informed party. This is important when addressing problems such as adverse selection and moral hazard. Moreover, screening allows for efficiency as it enhances the flow of information between agents as typically asymmetric information causes inefficiency. Screening is applied in a number of industries and markets. The exact type of information intended to be revealed by the screener ranges widely; the actual screening process implemented depends on the nature of the transaction taking place. Often it is closely connected with the future relationship between the two agents. for example in job markets, when employers screen future employees through the job interview, they are able to identify the areas the employee needs further training on. This benefits both parties as it allows for the employer to maximise from employing the individual and the individual benefits from furthering their skill set. The concept of screening was first developed by Michael Spence (1973). It should be distinguished from signalling – a strategy of combating adverse selection undertaken by the agent(s) with more information.

Second degree price discrimination is also an example of screening, whereby a seller offers a menu of options and the buyer's choice reveals their private information. Specifically, such a strategy attempts to reveal more information about a buyer’s willingness to pay. For example, an airline offering economy, premium economy, business and first class tickets reveals information regarding the amount the customer is willing to spend on their airfare. With such information, firms can capture a greater portion of total market surplus.

One downfall of deploying screening techniques is the information gathered may be incorrect, this can therefore lead to inefficiency. For example, an unproductive employee may perform well in screening exams such as aptitude testing. However, as the employer is the uninformed party, they will not be able to notice these aspects until the individual has been employed, and therefore, the time and effort put into the employee causes inefficiency. Hence, it is important for industries to understand the biases involved when utilising screening techniques.

Typical screening processes in the insurance market involve looking at historic data and demographic information, however, these screening processes may lead to incorrect conclusions. For example, a young male would typically be seen as high risk however, this may not truly be reflected as they could be a safe driver. Therefore, insurance companies need to ensure that further information is gathered prior to concluding what category individuals suit.

In contract theory, the terms "screening models" and "adverse selection models" are often used interchangeably. An agent has private information about his type (e. g., his costs or his valuation of a good) before the principal makes a contract offer. The principal will then offer a menu of contracts in order to separate the different types. Typically, the best type will trade the same amount as in the first best benchmark solution (which would be attained under complete information), a property known as "no distortion at the top". All other types typically trade less than in the first best solution (i. e., there is a "downward distortion" of the trade level). Optimal auction design (more generally known as Bayesian mechanism design) can be seen as a multi agent version of the basic screening model. Contract theoretic screening models have been pioneered by Roger Myerson and Eric Maskin. They have been extended in various directions. For example, it has been shown that, in the context of patent licensing, optimal screening contracts may actually yield too much trade compared to the first best solution. Applications of screening models include regulation, public procurement, and monopolistic price discrimination. Contract theoretic screening models have been successfully tested in laboratory experiments and using field data.