Almost all economic activity takes place under uncertainty. The randomness may, for instance, relate to risky stock market returns, fluctuating exchange rates or uncertain product innovations. The major source of uncertainty in decision making is the limited and imperfect knowledge of the decision maker at that given point in time. The exposure to uncertainty depends therefore inherently on the available information about the distribution of the existing risks. In general, information is imperfect itself. It may be more or less reliable and, in turn, it reduces the uncertainty to a greater or lesser extent. In economic theory a still growing literature deals with the question how uncertainty and information affect decisions and outcomes on the individual and on the aggregate level. This work aims to contribute to the understanding of what exactly more reliable information may mean and how this can be formalized. A number of informativeness concepts for information structures is related to each other and a general characterization is introduced. On this basis, moreover, the role of information about uncertain factor prices in the context of a single competitive firm and a small open economy is examined.