In professional diving, checklists are used in the preparation of equipment for a dive, and to ensure that the diver and life support systems are fully prepared before they enter the water. To a lesser extent, checklists are used by a minority of recreational divers, and by a larger proportion of technical divers during pre-dive checks. Studies have shown checklists to be effective at reducing the number of errors and consequent incidents.
A checklist is a type of job aid used to reduce failure by compensating for potential limits of human memory and attention. It helps to ensure consistency and completeness in carrying out a task. A basic example is the "to do list". A more advanced checklist would be a schedule, which lays out tasks to be done according to time of day or other factors. A primary task in checklist is documentation of the task and auditing against the documentation.