Disadvantages of consumer panels are:
1. Problem of Motivation Study
It is difficult to study and analyse motivations or attitudes on a continuous basis. After the first interview, panel members are alerted and are tempted to develop such attitude which would be like by all.
2. Accuracy of Data
The accuracy of the data is likely to be influenced by boredom and monotony due to repeated interviews, fatigue form completing diaries on regular basis.
3. Sample Selection
A panel consists of a small number of individuals representing the general character. In other words the highest and the lowest social classes are not being given due representation in the sample. Therefore, the sample may not represent the true picture of the population.
4. Panel Members
The panel members are selected on permanent basis but due to death, change of location, a resignation etc. necessitates replacements. However, replacing new member with the same characteristics is not easy.
5. Member Bias
The members of a panel develop of critical set and hence cease to be representatives of the general public. It is quite possible that being a panel member may tempt the person to change his attitude and opinion. There is every possibility of the panel members purposefully sticking to one type of attitude for a long time.
6. Interest Declines
In the initial period, everybody likes to become member and work for panel once the newness or novelty is over, interest may decline and members start working mechanically.