Information asymmetry

Information asymmetry is a concept in economics and contract theory. It says that in any given contract the two parties of the contract do not have the same information. Information economics is a field of science that looks at some of the problems that result from this bias. Neoclassical economics assumes there is perfect information: all the actors know all the states of their environment; they can also observe what all the other actors do. Information is free -it has no cost in the economic sense. This is also true for the ability to observe the other parties.
Model.
A model called New institutional economics changes this: information is no longer free, there are costs associated with obtaining information.
Information asymmetry is concerned with three main asymmetries:
History.
In 2001, the Nobel Prize in Economics was awarded to George Akerlof, Michael Spence, and Joseph E. Stiglitz "for their analyses of markets with asymmetric information."