Some of the disadvantages of self-report measures are as follows:
- People may lie or skew their answers to make themselves look better. For example, people tend to report higher happiness scores when the researcher is of the opposite sex!
- The person may not be able to give an accurate response due to cognitive biases, poor memory, etc.
- People may not have as much self-knowledge as the researchers assume (for example, psychoanalysts would argue that many feelings and much information is unconscious and protected by defence mechanism)
- Technically, they measure a perceptions of a construct rather than measuring it directly, and researchers must assume that this perception is an accurate enough reflection of the ‘real’ thing to be useful