Questionnaires are a cost-effective, simple and quick way to gather data that comes straight from the sources. This research method has been used for decades to gather data en masse, but it comes with its own complications and setbacks.
One of the benefits of designing a questionnaire is the privacy that it affords to its subjects. With a questionnaire, all of the subjects' responses are written down and submitted. The data never passes through anyone's hands but those of the data gatherers and the clients. Booths can be assembled to keep answers secret while the subjects are completing the questionnaire.
Cost is another bonus and a significant reason why many researchers use questionnaires. Making questionnaires both quick and very cheap; the questionnaire can be printed out and distributed physically, or the questionnaire can be completed and submitted online. There may be minimal costs, such as printing costs or hosting fees.
Customization is an important part of gathering research. One can determine how the subjects receive the study, the length of the questionnaire and what sort of questions are on it.
The drawbacks include the questionnaire's overall reach. The questionnaire can really only ask questions, it is not capable of performing full experiments.