Statistical infrequency is any behaviour which is numerically uncommon and therefore not seen very often in society.

Example: 95% of IQ scores in the general population are between 70 - 130. Any outside are considered abnormal.

Evaluation

Some statistically infrequent behaviour can be positive

Type: Limitation

  • Some statistically abnormal behaviour can be positive, because the behaviour is statistically abnormal does not mean the requirement of treatment
    • i.e., IQs over 130 are just as unusual as below 70
  • Therefore, statistical infrequency should never be used alone to make a diagnosis

Cut-off points are subjectively determined

Type: Limitation

  • Cut-off points are subjectively determined
    • People disagree on what constitutes an abnormal lack of sleep and since it is a symptom of depression, it is important to know where the cut-off point lies for a diagnosis to be made
  • This means that disagreements about cut-off points make it difficult to define abnormality

Cultural relativism

Type: Limitation

  • Classification systems like the DSM are based on Western cultures
  • However, cultures differ in terms of statistical infrequency and social norms
  • Therefore, there are no universal standards or rules for labelling behaviours as abnormal