Complete information is a term used in economics and game theory to describe a economic situation or game in which knowledge about other market participants or players is available to all participants and is instantaneously updated as new information arises. Every player knows the payoffs and strategies available to other players. Economics (deriving from the Greek words οίκω [oeko], house, and νέμω [nemo], distribute) is the social science that studies the allocation of scarce resources through measurable variables. ... Game theory is a branch of applied mathematics that uses models to study interactions with formalised incentive structures (games). It has applications in a variety of fields, including economics, international relations, evolutionary biology, political science, and military strategy. ...

Complete information is one of the theoretical pre-conditions of an efficient perfectly competitive market. In a sense it is a requirement of the assumption also made in economic theory that market participants act rationally; if one could not assume that all the market participants had all the information available, then one would have to model and forecast how the market would be affected by the uneven distribution and delayed diffusion of information. In economic theory, perfect competition is a market form in which no producer or consumer has the power to influence prices in the market. ... Economics is the social science studying production and consumption through measurable variables. ...

In practice, the assumption of complete information is unlikely to be correct for real world situations. For example, in the stock market, even the most sophisticated financial investors do not receive information instantly and do not react to it instantly. The large financial firms that have institutionalised the financial markets are overwhelmed with the volume of information that they are required to digest. Many of their major decisions are taken by committees or small groups of people that take time to convene, discuss, analyse and take decisions as to what to do. It can take a long time for major institutions to move their funds from one asset to another because they have to manage market impact (the effect of their own actions on asset prices). A stock market is a market for the trading of publicly held company stock and associated financial instruments (including stock options, convertibles and stock index futures). ...

Chess and yahtzee are complete information games while Scrabble and poker are not. From left, a white king, black rook and queen, white pawn, black knight, and white bishop in Staunton chess pieces. ... Yahtzee is the trademarked name of a popular dice game made by Milton Bradley (now owned by Hasbro). ... Scrabble board in play. ... The poker room at the Trump Taj Mahal, Atlantic City, NJ. Poker is a card game, the most popular of a class of games called vying games, in which players with fully or partially concealed cards make wagers into a central pot, after which the pot is awarded to the...

Certain information

A distinction is made by some authors of game theory literature between complete and certain information. In this context, complete information is used to describe a game in which all players know the type of all the other players, i.e. they know the payoffs and strategy spaces of the other players. Certain information is used to describe a game in which all players know exactly what game they are playing in the sense that they know what the payoff of playing a particular strategy will be given the strategies played by other players. An equivalent way of making the distinction, particularly helpful in the context of extensive form games, is to define a game of incomplete information as any game in which nature moves first and to define a game of uncertain information as any game in which nature moves after the players have moved.

See also

• Market impact
• Perfect information
• Extensive form game