Deciding is a pervasive activity. Decisions are taken in a variety of circumstances and involve significantly different processes. A situation could be complex but recurring. Although the term certainty is used it is doubtful whether a situation involving decision making is ever certain. In parallel with the variety of kinds of decisions there is a range of approaches to decision making. The approach should be appropriate to the nature of the decision problem, and the context in which it resides, and is influenced by the temperament of the decision maker. Every decision is tested against reality and the monitoring or evaluation of its operation in practice is vital. In organisations with mechanistic structures suitable for conditions of low risk and standardised technology and where the work force is not regarded as either professional or highly skilled, the management hierarchy will tend to dominate the decision-making process and to ensure that the implementation of decisions is closely supervised.