Web-based experiments and questionnaires are vital epidemiologic techniques that provide important information about public health and disease. They are a common means of collecting data that is often less expensive and time-consuming than face-toface interviews, mailed questionnaires or automated menus for telephone systems. Questionnaires and Web tests are not without their limitations, which must be addressed in order to obtain valid and reliable results.

A questionnaire can be affected by response bias. This is the tendency of respondents to answer questions based on their own opinions, rather than research objectives. In addition, the design of the questionnaire can affect responses in several ways: for example, question wording may influence whether respondents understand and interpret the question in the same manner (reliable), measure the subject matter you’re interested in (valid), or are able to answer accurately (credible).

Respondents may also experience fatigue or a lack of engagement with the questions being asked, which reduces the likelihood of them offering honest answers. A lack of incentives or compensation can also deter respondents from filling out survey forms.

Online questionnaires pose challenges for some go to website experiments, for example, positioning or reaction time studies. The variability in browser settings, screen sizes, and operating systems makes it difficult to measure and control the same variables across different participants.

Finally, web-based surveys may only be accessed by people who have keyboards and Internet proficient. This excludes a substantial segment of the population. In addition, it’s usually difficult to Web researchers to provide feedback to participants after the experiment’s time-out.