IV. COORDINABILITY AND CONSISTENCY IN SOCIOTECHNICAL SYSTEMS The concept of coordinability and consistency will now be introduced and an attempt will be made to show how the same is related to accident causation. In other words, the principle of coordinability and consistency will be used to find the point of failure in the sociotechnical system which resulted in an accident. It may be argued that such an approach for accident causation is relatively old, however the attempt being made in this paper is to show that coordinability and consistency can be applied to modern systems as well, showing that it is still an important concept till date for system safety. All sociotechnical systems are multilevel systems. The design and analysis of such systems is usually broken down into subsystems in a in a hierarchical structure.  A diagram of a standard two-level hierarchical system is shown in Fig 4, where, as expected, two levels can be found, namely the lower level and the upper level. The lower level consists of the process level, where the process level has been divided into N sub-systems. The sub-systems are connected to each other because there is either material or information flows between these sub-systems. Each sub-system has its own decision unit, which tries to control the behavior of the sub-system so that the objectives of this particular sub-system would be met. The decision unit can also use feedback information from the sub-system to improve its’ control policy’. However, quite often the objectives of the sub-systems are conflicting, resulting in a poor overall performance. A system in this context is defined as a function S: UY between a set of inputs U and a set of out-puts Y. In particular, a decision-... ... middle of paper ... ...n thus be seen that lack of consistency was used to identify accident causation. VI CONCLUSION Any given sociotechnical system can be operated and used safely if and only if coordinability and consistency are ensured from each level of the hierarchy to the next. It has also been shown that the lack of any one of these two terms will result in an accident, and it can successfully be said that coordinability and consistency can be used for identifying accident causation from where further investigations can take place. It must be remembered that there is nothing more difficult to plan, more doubtful of success, nor more dangerous to manage than the creation of a new system. As systems become more and more sociotechnical, more complex and more hybrid ensuring that the concept introduced above holds true will assist us in developing more safe systems.