Statistical infrequency

• Statistical infrequency - Occurs when an individual has a less common characteristic
• Statistical infrequency:

  • Statistics are about numbers
  • Any relatively usual behaviour or characteristic can be thought of as 'normal', and any behaviour that is unusual is 'abnormal'
• Example: IQ and intellectual disability disorder

  The normal distribution - The average score of IQ

  • Average IQ is set at 100, in normal distribution, most people have a score in the range of 85 - 115
  • Only 2% have a score below 70 - these are very unusual or 'abnormal' and are liable to receive a diagnosis for intellectual disability disorder
• Strength of Statistical infrequency: USEFULNESS

  • Used in clinical practice - part of formal diagnosis and way to assess severity of an individual's symptoms
  • Example: Diagnosis of intellectual disability disorder (IQ below 70)
  • Link: Useful in diagnostic processes
• Weakness of statistical infrequency: Not all infrequent behaviours are abnormal

  • They can be positive as well as negative
  • Example: For every person with an IQ below 70, there is a person with an IQ above 130. Yet we would not think of someone as abnormal for having a high IQ
  • Link: It is never sufficient as the sole basis of defining abnormality