Q. Show Difficulties in Evaluation advertising effectiveness?

Difficulties of example methods:- Approximately all methods of evaluating advertising effectiveness are on the basis of sampling. Some respondents as well as market area are selected for measuring effectiveness. It may perhaps involve following difficulties:-

a) Selected Sample Units mayn't be representative of whole group or area.

b) Simple Size may be extremely small in comparison to total no of actual-buyer.

c) The area certain as control area or test area may perhaps differ in terms of economic or demographic features.

d) Selection of easy Unit may be biased.