statistical frequency

• the most logical way to define abnormality is in terms of statistical infrequency.

  specifically, a behaviour is deemed abnormal if it is extremely rare
• we use descriptive statistics to help us understand the concept of abnormality

  such as mean, median and mode

  if we can define what is most common or normal, then we also have an idea of what is uncommon, i.e. abnormal.
• evaluation


  using statistics makes this an objective an unbiased way of defining abnormality

  • eg. finding people in a population more than 2SDs from the mean can be done objectively and without bias
  • however... the exact cut off point that you use to determine 'abnormality' may still be subjective

  defining abnormality using statistics is sometimes appropriate, especially when used in combination with other measures
• labelling is powerful and might affect people in a negative way. if you give them a label, they might start acting in a way that fulfils the label.

  some people are ''abnormal'' but leas happy and fulfilled lives. if we label someone then we run the risk of developing a self fulfilling prophecy
• however, statistically unusual features can also be desirable, rather than just negative

  • there are lots of circumstances where specific rare behaviours are considered desirable - such as IQ