In this method, the investigator for the purpose of collecting data makes a questionnaire, gets it published and sends it to the informants either through post or either personally delivers them. Informants are ensured that the information given by them will be kept as a secret. Informants fill the questionnaire and by a sepecified date send them back to the investigators.
Use of Method :
1. This method is suitable for that wide area where the informants are literate.
2. This method is suitable for opinion polls and information about consumers’ interests.
Merits of Method :
1. This method is useful for a large area.
2. There is less expenditure of money, time, and labour. .
3. The information is original.
Demerits of Method :
1. Mostly the results are impure.
2. Informants do not take interest in giving information.
3. Information is incomplete and improper.
