The Postal survey is another technique for collecting relevant informations. In fact, it gives respondents time to think and answer the questions calmly. In a mail survey, the questionnaire is mailed directly to the people in the sample. Each questionnaire is accompanied by a stamped envelope for sending the answer.
The mail survey has always had a low return rate. Thus, to encourage people to respond, some companies organize contests. The promise of a gift to those who respond in a timely manner is also effective. There is another problem with the mail survey. In fact, a large number of responses are unusable because the questionnaires are either :
Some people also answer the questions asked without following the instructions given.