The GAF Scale is useful and can be used to assess the severity of a condition by putting the individual at the heart of the understanding and the treatment.
Most of the criteria is observable by the doctor, so we can see the effects and put treatment in place to help.
Sometimes the criteria may be experienced as part of normal life; it is normal to suffer 'personal distress' when a loved one dies.
This definition is subjective as it depends on the observer/ doctor recording the symptoms.
This definition is culturally specific, and depends on the norms of that society.
Using a set scale to measure behaviour is an objective way to record data.
Failure to function adequately can be seen by others around the individual, so can be validated.
In some cases, abnormality does not always stop the person functioning.
The ability to cope with everyday life depends on what is seen as normal everyday life.