I have this big dilemma that I thought that someone here could help me solve. I've got this project, that would require me to make a study, where people would have to fill out an electronic questionnaire on the Internet. But making an Internet-based study scientific, there are some problems that need to be solved.
First of all, if a questionnaire is available for anyone to answer on the web, there is a chance that somebody might manipulate the results of the study by entering more than once and/or giving out false information. This may be the case, where eg. companies or anyone else would want the study to give a certain result.
So, to avoid this, I would need to make a questionnaire wherethe user can fill out only once, and where several people can fill out the form from the same computer. As this study is aimed at 12-18 year olds, it's quite certain that quite many of them will access the questionnaire from computers at school.
I've been thinking how to solve this, but I just can't think about a good solution. One way of doing it would be to make the questionnaire only accept one submission per IP-address, but this would exclude anyone else trying to fill out the questionnaire from that computer.
Another way would be to ask the user for his/her e-mail address, so that at unique password would be sent to him/her to able to log on to the questionnaire. By doing this however, you first of all exclude everyone without an e-mail address, and also those who think it's too much trouble to fetch the password (especially if they have a web based e-mail account) or those who don't want to give out their e-mail address.
So you see, I'm in a quite big dilemma here. I know that some of you might wonder why I just don't do this the old-fashioned way - in paper form - but the reason why is simple: I won't have time to collect and analyze the results manually.
I've posted here before asking if anyone knows how to make a good questionnaire, so if anyone still could help me, I'd really appreciate it.