Strengths - Statistical Infrequency:
- This definition is neutral - it makes no judgement about the value of an abnormality. This is an ethical advantage, since it avoids negatively stigmatising people who are abnormal - they are simply different.
Limitations - Statistical Infrequency:
- It can be argued that we need to distinguish between abnormality which is 'good' or 'bad', which this definition fails to do. EG: very high IQ would be seen as an advantage whereas a very low IQ would be a disadvantage, so it doesn't make sense to label them both as abnormal. Similarly, some undesirable characteristics, like anxiety and depression are relatively common and so would be considered as normal according to this definition. Therefore this definition alone cannot be used to determine abnormality because it creates too many 'false positives' and 'false negatives'.
- It is unclear where the cut-off point between normal and abnormal should be, so there is no agreement about how rare a behaviour needs to be before it is considered abnormal. This reduces the usefulness of this definition.