Human factors & adverse events

Accidents in certain areas can be catastrophic. Think about accidents in nuclear power generation or air transport. Between the forties and the eighties, this became a main concern of the human factors specialists.

Sparkling interest in human factors in the medical profession

After the eighties, several scientists started investigating the reliability of the medical provisions. This community arose on two levels. At the doctor-patient interface (also called “sharp end”) common features include uncertain and dynamic environments, sources of concurrent information, changing and badly defined goals, actions having immediate and/or multiple consequences, the combination of time stress and routine activities, advanced but limited new technologies, confusing human-machine interfaces and multiple players with different interfering goals. There is however also a second, organizational level. There, these activities are being carried on within complex institutional settings. They entail several interactions between different professional groups.

There is a growing concern for human factors in health care. Fortunately, the models of accident causation that were developed for other domains, can be applied to the medical domain as well.

Human errors

Since the sixties there has been an increase in the amount of human errors when it comes to accidents with hazardous technologies. A possible explanation for this might be that equipment has become more reliable. The accident investigators have become more aware that errors are not only restricted to the ‘sharp end’. They realize now that human errors cannot all be put in the same group, they can be very different and have very different causes and consequences.

Human errors can be classified based upon their causes or their consequences. Classifications based on consequences describe the error in terms of the proximal actions that contributed to the mishap (e.g. wrong intubation). Classifications based on causes make assumptions about the psychological mechanisms implicated in creating the error.

Slips, lapses and mistakes

An error is being defined here as the failure of planned actions to achieve their desired goal. There are two ways in which that can occur. Either the plan is okay, but the actions do not go as planned. These failures are called slips and lapses. Slips are attentional failures and relate to observable actions. Lapses are failures of memory and relate to internal events. Or the actions do go as planned, but the plan is not good and they do not achieve the intended outcome. These failures of intentions are called mistakes. There are rule based mistakes and knowledge based mistakes. Rule based mistakes relate to problems for which the person has some solution, which he got as the result of training, experience, or the availability of appropriate procedures. The mistake can either be the misuse of a good rule, the use of a bad rule, or the non-use of a good rule. Knowledge based mistakes occur in novel situations where the solution to a problem has to be worked out in the moment, without any help of already ready solutions.

Errors and violations

Violations are defined as deviations from safe operating practices, procedures, standards, or rules. Violations can be divided in three categories. Routine violations entail cutting corners whenever the opportunity arises. Optimising violations are actions that are being taken to further personal goals instead of only task-related goals. Situational violations occur when the violation itself seems to be the only way of reaching the intended goal, and the rules and procedures that are in place in that moment seem to be inappropriate.

Differences between errors and deliberate violations

First of all, errors arise mostly from informational problems, such as forgetting and not paying attention. Violations are more associated with motivational problems, such as a lack of motivation or poor supervision. Secondly, violations occur in a regulated social context. Errors on the other hand occur by what goes on in the mind of the person. Finally, violations can be reduced by motivational and organizational solutions. Errors require quality improvement and the delivery of necessary information.

Active and latent human failures

The difference between active and latent human failures is based on the amount of time that passes before the failures have a negative effect on the safety. With active failures, the negative effect is nearly instantaneous. For latent failures it can take a very long time before the negative effect is shown.

Another difference between active and latent human failures is the level in which the failures are made. Active failures are made by those at the ‘sharp end’. They are the people at the human-system interface, and their actions can have immediate negative consequences. Latent failures arise as the result of decisions taken at the higher organizational level. It may take some time before the effects of their decisions become visible, for instance because the effects don’t occur unless in combination with certain factors that arise after a long time.

Stages of development of organizational accidents

The accident start with the negative consequences of organizational processes (e.g. bad planning, scheduling, designing, communicating). This is how the latent failure is created. It is then transmitted along various organizational pathways to the workplace. Here they create the local conditions, which in turn increase the commission of errors and violations. For instance through a high workload or too little staff.

Risk management

Risk management usually focuses on introducing new procedures, sanctions, guidelines and increased automation. There are however serious problems with this strategy. People don’t intentionally make errors. It will be hard for others to control what the employees cannot even control themselves. Even harder to control will be the psychological factors that are related to errors, such as stress and fatigue. Also, accidents are hardly ever the consequence of a single unsafe action; they are the product of many different factors as we have seen. Finally, the countermeasures can be interpreted as a false sense of security.

Effective risk management should focus on enhancing human performance in all the levels of the system, and not just on minimizing certain errors.

Team, task, situational and organizational factors

• Teamfactors. Improvements in team management and communication can seriously improve human performance. Improving institutional performance is expensive, whereas team performance can be improved much cheaper and easily through training.

• Taskfactors. It is very important to identify and modify tasks that might cause failures.

• Situational factors. Certain conditions increase error probabilities, such as a high workload, inadequate knowledge, experience, bad interface design, bad instructions or supervision, stress, mental state and change. Conditions that increase violation probabilities are a lack of safety culture, a lack of concern, a poor morale, having norms that condone violation, a can-do-attitude and meaningless/ambiguous rules.

• Organizational factors. The core of the organization should be checked regularly, to improve proactive accident prevention (instead of reactive little repairs). The health of the organization can be investigated by looking at the organizational factors that played a role during accidents, and by looking at the core processes that are common in all technological organizations.