Children whose chronological age is in the range 1 to 16 years and who have had a history of normal development. If the child’s history of development has not been normal then another category might be more appropriate, for example Developmental Problems or Psychological Illness.

On or off route, accessing into or out of the climb.

This category contains all missing persons with some form of dementia, including those with Dementia of Alzheimer’s Type. Gibb and Woolnough's Grampian Study provides a useful discussion on different forms of dementia.

Any person who is thought to have disappeared deliberately.

This category refers to missing persons with a mental age that is very different from their chronological age.

Either a competitor in an event, or training, or out for a recreational run, or orienteering.

A person who has gone missing primarily as a result of problems relating to their health; a person whose behaviour is influenced by their current medical condition.

A walker of any age who is thought to be on their own and engaged in walking as a recreational activity; they might have become detached from a group.

Any missing person who can not be assigned to one of the other categories, for example a walkaway from a road traffic accident.

Missing persons for whom the bicycle was the main means of transport, on or off road.

A group of two or more persons of any age of the same or mixed gender engaged in any form of recreational walking; examples are a group on a DoE expedition, cadets on a march or a group of people walking together in an informal manner.

This category refers to missing persons with significant mental impairment other than those covered by the categories Dementia, Developmental Problems, Health Related, Psychological Illness and Substance Related.

Persons identified by a medical practitioner as suffering from a mental illness; they may be undergoing treatment, either at home or in an appropriate unit. Gibb and Woolnough's Grampian Study provides a useful discussion about some of these illnesses.

A person for whom abuse of alcohol or drugs played a significant part in their being missing.

Persons engaged in activity on or in water, for example missing swimmers, fisherman, or people who fell in. Gibb and Woolnough's Grampian Study provides a useful discussion about bodies missing in water.