AO3

• strength:

  P - it is used in clinical practice

  E - a diagnosis of intellectual disability disorder requires an IQ of below 70, so a person would score in the bottom 2% of the population

  E - an example of it being used in an assessment tool is becks depression inventory as a score of 30+ (top 5%) is widely interpreted as indicating severe depression

  C - this shows the real world value of this definition over others such as deviation from social norms as this is not used as much within diagnosis or assessment tools
• Limitation:

  P - it fails to account for the fact that infrequent behaviours can be positive as well as negative

  E - we would not think of someone as having a high IQ as abnormal, however scores over 130 only occur in the top 2% of population so are rare

  E - we would not think of someone with a very low depression score on the Beck depression investory as abnormal, even though this would be bottom 5%

  C - definition is not always accurate in defying abnormality so it should not be used as sole definition