Web-based questionnaires and questionnaires are an essential method of epidemiology that provide crucial information about the state of public health and diseases. These are the most common methods for collecting data. They are typically cheaper and less time-consuming than face-toface interviews, mailed questionnaires, or automated telephone menu systems. However questionnaires and Web experiments are not without limitations that should be addressed to ensure that they are reliable and valid results.

A questionnaire can be affected by response bias. This is the tendency of respondents to answer questions based on their personal opinions rather than the research objectives. Furthermore, the design of a questionnaire can influence responses in different ways. For example, question wording may influence whether respondents are able to comprehend and interpret the questions in the same way (reliable), measure what you’re looking for (valid), or are able to answer accurately (credible).

Respondents can also experience survey fatigue or lack of engagement with the questions being asked which reduces the chances of them providing honest answers. In addition, a lack of incentives or monetary compensation could make it difficult for respondents to take the time to fill out an application.

Online questionnaires pose challenges for some experimental designs, like reaction-time or positioning studies. The wide range of settings for browsers screens, sizes, and operating systems makes it difficult to measure and control the same variables for different people.

Furthermore, Web-based surveys are only accessible to those who are keyboard and Internet literate, which currently excludes a significant percentage of the population. In addition, it is often hard for Web researchers to inform participants after the experiment’s time-out.