Evaluation

• Real-world application

  One strength of statistical infrequency is its usefulness:

  • It is used in both diagnosis and to assess severity of symptoms
  • E.g. Beck depression index (BDI). A score of 30+ is interpreted as severe depression
• Unusual characteristics can be positive

  One limitation of statistical infrequency is that infrequent characteristics can be positive as well as negative:

  • E.g. someone with an IQ of over 130 is infrequent, just as a score of below 70 is. Or someone with a low score on the BDI.
  • These examples show that being at one end of the spectrum does not necessarily make someone abnormal
  • Therefore, statistical infrequency is not sufficient as a sole basis for defining abnormality