Web-based questionnaires and experiments are vital epidemiologic techniques that provide vital information on public health and diseases. These are common methods of collecting data, which are often more affordable and efficient than face-toface interviews, mailed questionnaires, or automated phone menu systems. However questionnaires and Web tests have some limitations that need to be addressed in order to ensure that they are reliable and valid results.
A questionnaire may be affected by response bias. This is the tendency of respondents to answer questions based upon their opinions instead of research goals. The design of a questionnaire may influence responses in a variety of ways. For instance the wording of the question may affect whether respondents are able to comprehend the question and interpret it in the same manner (reliable) as well as whether the question is a good indicator of the subject you are interested in (valid) and if they are able to accurately answer (credible).
A lack of enthusiasm or engagement with the questions can also cause respondents to be less inclined to give honest answers. A lack of incentives or compensation may also deter respondents from filling out an application.
Online questionnaires can also be challenging for certain experiment designs like studies of response time or positioning. It is challenging to measure and control variables across different participants due to the differences in settings for browsers as well as operating systems and screen sizes.
Additionally, surveys conducted on the Web are only available to people who have keyboards and are Internet proficient, which excludes a significant portion of the population. It’s also difficult to Web researchers to report on participants after the window for their experiment has closed.