Although questionnaires are often designed for statistical analysis of the responses, this is not always the case.
The other problem associated with return rates is that often the people who do return the questionnaire are those who have a really positive or a really negative viewpoint and want their opinion heard.
The people who are most likely unbiased either way typically don't respond because it is not worth their time.
For example, unlike interviews, the people conducting the research may never know if the respondent understood the question that was being asked.
Also, because the questions are so specific to what the researchers are asking, the information gained can be minimal.
This information about the quality can also be used in order to correct for measurement errors () Further, if the questionnaires are not collected using sound sampling techniques, often the results can be non-representative of the population—as such a good sample is critical to getting representative results based on questionnaires.
Questionnaire are of different types: 1)Structured Questionnaire. Warm-ups are simple to answer, help capture interest in the survey, and may not even pertain to research objectives.Transition questions are used to make different areas flow well together.Thus, for some demographic groups conducting a survey by questionnaire may not be concrete.A distinction can be made between questionnaires with questions that measure separate variables, and questionnaires with questions that are aggregated into either a scale or index.There typically is a flow that should be followed when constructing a questionnaire in regards to the order that the questions are asked.