I am writing an online survey and I am wondering if there are any good techniques for allowing anonymous people to go to the survey and participate and also prevent duplicates.
I have considered the following, but there are drawbacks from each:
Of the techniques I have considered, you either prevent multiple people from using the same device, or make it easy for a user to duplicate survey results. Hopefully someone has an excellent way to prevent this :)
Well I am not sure whether you are thinking of deliberate or accidental duplicates?
Was that what you were after?
I am currently investigating a similar scenario.
Some of the suggestions I found online are:
The clear limitation is that you require their email, and this is slightly lengthy. However, the email address is not associated with the answer set.
The problem with using email, ID numbers, and Birth Date; is that all of these values can be fabricated.
If this approach is used, also do not forget good old CAPTCHA, as a script can be created to run through the combinations and submit answer sets.
I realize this is an old post, but hopefully it helps someone at some point. All of the best.