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In decision theory, uncertainty is understood as the lack of knowledge about the future development of an environmental condition . Lack of knowledge describes a level of information at which the possible environmental conditions and the results of choosing a certain alternative course of action and the occurrence of a certain environmental condition are known, but the (subjective and objective) probability of occurrence of the environmental conditions is unknown. It's a subspecies of insecurity . Linguistically, uncertainty is the negation of certainty .


The specialist literature on business administration and decision theory uses the terms uncertainty, uncertainty and risk inconsistently. The classification of situations of non-safety in those (under risk english risk ) and uncertainty ( english uncertainty ) is the American economist Frank Knight attributed that in 1921 in a seminal work with risk and uncertainty in achieving profits dealt . The term "uncertainty" used by him can be translated both with uncertainty and with uncertainty. In the sense of Knight, uncertainty always arises in the case of one-off, non-repeated decisions . The economic function of the entrepreneur therefore consists in entering into unpredictable uncertainties (uncertainties). There were two choices for Knight, risk and uncertainty. For Kenneth Arrow , uncertainty is the complement of knowledge . The ambivalent translatability of "uncertainty" has contributed to the inconsistent use of the terms uncertainty and uncertainty in German specialist literature. Waldemar Wittmann therefore spoke in 1959 of "uncertain knowledge", which "is expressed in an indeterminacy of judgment", according to which uncertainty is the "lack of or lack of certainty". In 1999 the German specialist literature followed Knights Concept and knows two types of imperfect information, namely the risk and the uncertainty, which can be a partial or total uncertainty.

Level of information

In numerous operational decision-making situations, no or hardly any usable information has to be obtained in advance of the decision . The consequence of this imperfect information is the uncertainty about the effectiveness of the result of the decision; Uncertainty arises from the decision-makers ' awareness that there is a discrepancy between necessary and available information. The level of uncertainty is expressed in inverse proportion to the degree of information. The resulting risk of a wrong decision is based on inaccurate data (incorrect or insufficient information) or on errors in thinking and arithmetic of the decision maker when evaluating the data and making the decision. There is, however, much information, so that may information costs the information value does not exceed. A lot of information increases the level of information and, in the optimum as complete information, can lead to an information level of 100% - a decision is made under security as the opposite of uncertainty.

Decision under uncertainty

The most important form of uncertainty is the decision under uncertainty . If probabilities of occurrence can be determined (objective through data evaluation , subjective through estimation and experience ) and these can be used as a basis for a decision , it is a decision under risk . If, on the other hand, there are no probabilities of occurrence, a decision is made under uncertainty. A probability of occurrence is used when empirical data is available or can be calculated for the alternative courses of action of a decision. The decisive factor for the distinction between uncertainty and uncertainty is the probability of occurrence, which fluctuates between 0 (will not occur) and 1 (will definitely occur). The probability distribution of possible future environmental conditions is unknown when the decision is made under uncertainty; no probabilities of occurrence can be assigned. However, it can be assumed that one of several anticipated results of an alternative course of action will arise. Decisions under uncertainty do not represent economic decisions, but occur in game situations ( dice games , lotteries ).


The majority of German literature today is of the opinion that uncertainty and insecurity are not synonyms . In the event of uncertainty, the planner or decision maker has (subjective and / or objective) probabilities of occurrence; on the other hand, in the context of uncertainty, he completely lacks them. Here he can only assume that one of several expected results will occur.


Individual evidence

  1. ^ Frank Knight, Risk, Uncertainty, and Profit , 1921, p. 20
  2. ^ Frank Knight, Risk, Uncertainty, and Profit , 1921, pp. 233 f.
  3. Kenneth Arrow, Alternative Approaches to the Theory of Choice in Risk-Taking Situations , in: Econometrica, Vol. 19, 1951, p. 404
  4. Waldemar Wittmann, Entrepreneurship and Imperfect Information , 1959, p. 28
  5. Waldemar Wittmann, Entrepreneurship and Imperfect Information , 1959, p. 28
  6. Andreas Kleine, Imperfect Information in Leontief Technologies , in: Zeitschrift für Betriebswirtschaft, Supplement 4/99, p. 23
  7. Dieter Schneider, Investment and Financing , 1971, p. 65
  8. ^ Waldemar Wittmann, Information , in: Handwortbuch der Organization, 1980, Sp. 897 f.
  9. ^ Waldemar Wittmann, Entrepreneurship and Imperfect Information , 1959, p. 29
  10. Wolfgang Hoffmeister, Investment calculation and utility value analysis , 2008, p. 187
  11. www.springer.com