Web-based surveys and questionnaires are a vital epidemiologic technique that provide crucial information about the state of health and disease in the public. These are common methods of collecting data, which are typically less costly and time-consuming than face-toface interviews, mailed questionnaires, or automated telephone menu systems. However questionnaires, surveys and Web experiments are not without limitations that need to be addressed in order to ensure reliable and valid results.
A questionnaire can be affected by response bias. This is the tendency for respondents to answer questions based on their personal opinions and not on research goals. The design of a questionnaire can influence responses in various ways. For instance, the wording of the question could affect whether respondents are able to comprehend the question and interpret it in the same way (reliable) or whether the question is relevant to the subject you are interested in (valid) and if they are able to accurately answer (credible).
A lack of engagement with the questions can also cause respondents to be less inclined to provide honest answers. Additionally, a lack of incentives or compensation could dissuade respondents from taking the time to fill out the questionnaire.
Online questionnaires also pose challenges for certain experimental designs, like positioning or reaction-time studies. The varying settings of browsers, screen sizes, and operating systems makes it challenging to measure and control the same variables for different people.
Furthermore, Web-based surveys are only accessible to those who have keyboards and are Internet literate, which currently excludes a significant portion of the population. It’s also difficult for Web researchers to report on participants after the window for their experiment has ended.