Web-based experiments and questionnaires are essential epidemiologic tools that offer vital information about public health and disease. They are a common method of collecting data that are generally cheaper and less time-consuming than face-toface interviews, mailed questionnaires, or automated telephone menu systems. However questionnaires and Web experiments have a number of limitations that must be addressed to ensure valid and reliable results.
A questionnaire may be affected by response bias. This is the tendency of respondents to answer questions based upon their opinions rather than the research objectives. The structure of a questionnaire can influence responses in a variety of ways. For example the language of the question can affect whether the respondents comprehend the question and interpret it in the same manner (reliable) and whether the question reflects what you’re interested in (valid), and whether they can accurately answer (credible).
Respondents may also experience fatigue or lack of interest business with virtual boardroom in the questions that are asked which decreases the probability of them providing honest responses. Lack of incentives or compensation can also discourage participants from filling out survey forms.
Online questionnaires can be challenging for certain experiment designs such as studies of response time or positioning. The variability in browser settings size, screen sizes, and operating systems makes it difficult to control and measure the same variables across different participants.
The bottom line is that Web-based surveys can only be accessed by people who are keyboard and Internet knowledgeable. This excludes a substantial portion of the population. Furthermore, it’s usually difficult for Web researchers to inform participants when the window for an experiment has closed.
