Under this method, a list of questions pertaining to the survey which is known as ‘Questionnaire’ is prepared and sent to the various informants by post. Sometimes the researcher himself too contacts the respondents and gets the responses related to various questions in the questionnaire.
The questionnaire contains questions and provides space for answers. A request is made to the informants through a covering letter to fill up the questionnaire and send it back within a specified time.
The questionnaire studies can be classified on the basis of:
a. The degree to which the questionnaire is formalized or structured.
b. The disguise or lack of disguise of the questionnaire and
c. The communication method used.
When no formal questionnaire is used, interviewers adapt their questioning to each interview as it progresses. They might even try to elicit responses by indirect methods, such as showing pictures on which the respondent comments. When a researcher follows a prescribed sequence of questions, it is referred to as a structured study. On the other hand, when no prescribed sequence of questions exists, the study is non-structured.
When questionnaires are constructed in such a way that the objective is clear to the respondents then these questionnaires are known as non- disguised; on the other hand, when the objective is not clear, the questionnaire is a disguised one. On the basis of these two classifications, four types of studies can be distinguished:
1. Non-disguised structured,
2. Non-disguised non-structured,
3. Disguised structured and
4. Disguised non-structured.
There are certain merits and demerits of this method of data collection which are discussed below:
1. Questionnaire method of data collection can be easily adopted where the field of investigation is very vast and the informants are spread over a wide geographical area.
2. This method is relatively cheap and expeditious provided the informants respond in time.
3. This method has proved to be superior when compared to other methods like personal interviews or telephone method. This is because when questions pertaining to personal nature or the ones requiring reaction by the family are put forth to the informants, there is a chance for them to be embarrassed in answering them.
1. This method can be adopted only where the informants are literates so that they can understand written questions and lend the answers in writing.
2. It involves some uncertainty about the response. Co-operation on the part of informants may be difficult to presume.
3. The information provided by the informants may not be correct and it may be difficult to verify the accuracy.
However, by following the guidelines given below, this method can be made more effective:
The questionnaires should be made in such a manner that they do not become an undue burden on the respondents; otherwise, the respondents may not return them back.
a. Prepaid postage stamp should be affixed
b. The sample should be large
c. It should be adopted in such enquiries where it is expected that the respondents would return the questionnaire because of their own interest in the enquiry
d. It should be preferred in such enquiries where there could be a legal compulsion to provide the information.