Questionnaires and web tests allow doctors to reach a much wider market than classic paper questionnaires, telephone or face-to-face interviews and is conducted for a fraction of the cost. This makes them a trendy tool for market research and customer surveys online as well as internal studies. However , inspite of their various advantages offered with some down sides which can weaken the validity of the benefits.
One serious problem is that at this time there is less control over data capture than with a paper customer survey. With a Web experiment the participant is able to view stimuli on their own personal device and may even also improve settings just like screen size, browser, internet connection and perhaps the standard font. This implies that each respondent activities a quietly different questionnaire and this may affect how they answer questions.
Another internet-based.org/internet-polls problem is customer survey taking fatigue which can cause respondents leaving the study. The way to avoid this is to make the questionnaire because short as is feasible and only inquire abuout that are highly relevant to your research. You may also try to randomize the buy of the questions and pretest the questionnaire prior to performing this to ensure that all the questions are clear and understandable.
Finally, you have to keep in mind that Web experiments depend on voluntary involvement so they can be a little more susceptible to motivational confounding than laboratory tests. To counter this kind of, you can use a web based marketplace including SONA devices (often employed for undergraduate examining at universities), MTurk or Productive to get participants.