Therefore, the working diver often faces greater pressure to provide the service at the cost of reduced personal safety. An understanding of the human factors associated with diving may help the diving team to strike an appropriate balance between service delivery and safety. Human factors are the influences on human behavior, and the resulting effects of human performance on a process or system. Safety can be improved by reducing the frequency of human error and the consequences when it does occur. Fitness to dive Fitness to dive is the medical and physical capacity of a diver to function safely in the underwater environment using underwater diving equipment and procedures. Psychological factors can also affect fitness to dive, particularly where they affect response to emergencies, or risk taking behavior. Some conditions affect fitness to function safely and effectively underwater in unpredictable ways, and may not be noticed until they show up under stress and precipitate an emergency. Other conditions do not necessarily prohibit the person from diving, but limit their ability to manage in difficult circumstances, and a realistic assessment of where the diver's personal limits lie can help prevent an emergency from developing. In professional diving, the diving medical examination is used to identify divers who are at risk in circumstances which are acceptable in a working environment. Recreational divers must take more personal responsibility for self-assessment before each dive. To some extent greater competence can mitigate a lower level of fitness, as the diver can correct mishaps more quickly and with less effort. Situational awareness Situational awareness is the perception of environmental elements and events with respect to time or space, the comprehension of their meaning, and the projection of their future status. It has been recognized as a critical, yet often elusive, foundation for successful decision-making across a broad range of situations. Lacking or inadequate situation awareness has been identified as one of the primary factors in accidents attributed to human error. The formal definition of situational awareness breaks it down into three components: perception of the elements in the environment, comprehension of the situation, and projection of future status. Situational awareness is recognised as necessary for diving safety, as a member of the dive team who is not aware of changing circumstances may fail to react appropriately in time to avoid serious difficulties. Situation awareness is limited by sensory input and available attention, by the diver's knowledge