Web-based questionnaires and experiments are essential methods of epidemiology that provide important information about public health and disease. They are a typical method of gathering data that is often less costly and time intensive than face-to-face interviews, mailed paper questionnaires or automated menus for phones systems. However questionnaires and Web tests have some limitations that must be addressed in order to ensure the validity and reliability of results.
A questionnaire may be affected by response bias. This is the tendency for respondents to answer questions based on their opinions instead of research goals. The design of a questionnaire can influence responses in many ways. For instance, the wording of the question could affect whether respondents are able to comprehend the question and interpret it in the same manner (reliable), whether the question is a good indicator of what you are interested in (valid), and if they are able to accurately answer (credible).
Respondents might also experience survey fatigue or a lack of interest in the questions and reduces the chance of them giving honest answers. A lack of incentives or compensation could make it difficult for respondents to fill out an application.
Online questionnaires pose challenges for some experiments, like reaction-time or positioning studies. The wide range of settings for browsers, screen sizes, and operating systems makes it difficult to measure and control the same variables across all participants.
Finally, Web-based surveys are only available to those who are keyboard and Internet literate, which currently isn’t a large portion of the population. It is also difficult for Web researchers to provide participants with a report after the window for their experiment has closed.