Statistical Infrequency

• Statistical Infrequency Defintion

  A person’s thinking or behaviour is abnormal if it is statistically rare and unusual. In any human characteristic, the majority of people’s score will cluster around the average, and the further we go above or below that average, the fewer people will attain that score. This is called normal distribution. Someone who is statistically infrequent will cluster at the top/bottom of this distribution graph (eg on an IQ distribution graph)
• (+) Objective Method

  This definition requires a clinician to measure out normal behaviour eg they can look at an IQ distribution curve and identify which scores could be classed as abnormal when diagnosing an intellectual disability disorder. This is a strength as it provides a practical method of diagnosing abnormality and does not rely on the subjective of the clinician. This means that a clinician is likely to make a more reliable and valid diagnosis using this definition
• (-) Not all abnormalities benefit

  Some characteristics can be positive and should not be classed as a psychological abnormality. IQ scores over 130 are just as rare/abnormal as IQ scores under 70 but we would not find being extremely intelligent as an unwanted/undesirable characteristic that would need treatment. According to the definition, this behaviour is still statistically infrequent/abnormal but doesn’t need treatment to return it to normal. This is a limitation because, if used alone, this definition could make an invalid diagnosis.
• (-)Culture Bias

  The normal distribution curve that abnormal behaviour is judged against may be affected by the culture that the data was gathered in and therefore may only reflect the statistical infrequency in one specific culture. This is a limitation because it might not be valid to use statistics from one culture to judge the rareness/frequency of behaviour in another culture, This could mean that the diagnosis is not valid and some people may be incorrectly labelled as abnormal, potentially leading to unnecessary drug treatment being received that would have negative side effects.
• (-) Labels are not always useful.

  When someone is living a happy and fulfilled life it is not necessary or beneficial to label them as abnormal, regardless as to how unusual they are. For example, someone with an extremely low IQ but is not distressed and quite capable of working/functioning normally would not need a diagnosis of intellectual disability. This is a limitation of the definition as a label may have a negative impact on the way others/themselves view them (stigma)