How can I prevent multiple registrations by the same person in my internet survey project? Obviously, the same person can have many email addresses as well as well as virtual phone numbers for registration. What would be the best approach to try stop or limit that.

  • Why do you not want them to register multiple times? What is the particular application?
    – Tim Holt
    Commented Jan 28, 2021 at 23:40
  • I think the lengths you go to to stop multiple registrations, really depends on what peoples' incentive is to do it in the first place. If your survey isn't monetized then you need a lower bar to stop multiple registrations. Is it monetized ?
    – PhillipW
    Commented Feb 28, 2021 at 14:02

5 Answers 5


I won't just link to the website, but Sweepstakes Entry Restrictions - Understanding the Rules is a good discussion of various kinds of rules for limiting entries to sweepstakes. Perhaps they will serve as a good guide to solving your challenge.

These all seem like reasonable approaches, though as pointed out there are always limitations to how effective they are. E.g., users at a coffee shop on the same IP address not being able to all register.

Quoting extensively from the article linked to above...

One Entry Per Person

Some sweepstakes state in their rules that only one entry is permitted per person (or one entry per person per day, or per week, etc.). This means that you, personally, can only enter once per time period. It doesn't matter if you use a different email address, home address, telephone number, your maiden name, your middle name - you can still only enter once. However, this restriction wouldn't prevent your spouse, your child, or your roommate from entering.

One Entry Per Email

For each email address that you have, you can enter one time per entry period. That means that if you have 200 email addresses registered, you can enter 200 times. However, you then need to check all of those addresses for win notices! What Does One Entry Per Person/Email Mean?

This designation means that each person can enter only once per time period, and also that the email address they use can only be entered once per time period. So you can't enter yourself repeatedly, and a friend or family member can't use the same email address that you did when they enter. Sometimes, sweepstakes rules will list these two restrictions separately. For example, the rules might say one entry per person, and then a little later they'll state that no two entrants may share the same email address.

One Entry Per Household

A one entry per household entry restriction means that only one person living at the address can enter the contest or sweepstake. It doesn't matter if the other person is a spouse, a child, or just a roommate, if you share the same home, only one of you can enter.

One Entry Per Computer

If you share your computer with other people like your spouse or your children, only one of you can enter any sweepstake with this entry restriction in its rules. This also means that you cannot enter on behalf of your mother, your best friend, or anyone else.

One Entry Per Internet Location or Per IP Address

A sweepstakes entry restriction of one entry per internet location means that only one person using your IP address can enter per time period. (For more information, see What Is an IP Address? from the Guide to Webdesign). Basically, this means that only one entry can be made from your internet account.

For example, my husband and I each have our own computers, but because we share the same internet service, only one of us could enter a sweepstake with this restriction. This can get tricky if you are entering sweepstakes from your office, from the computer lab at a university, or from a public location like a library or the local coffee shop, because you could be sharing an IP address with a lot of people.


I'm not sure this is a good idea (last resort perhaps), ask them to upload a photo of their ID in your survey project.


there are some services that provide a mix of IP-based location protection to limit answers by the same person.

Can you give the link individually? To avoid giving it in public?

can you also assign them an individual token so you know which ones are valid?


It is almost like you need to design a Voter ID System. Issuing a one-time password (OTP) to physically verified persons and witnessing them use it would achieve your desired results - probably impractical, but may or may not work for your use case.


Every user can have several emails, telephone numbers, etc.

Probably the only way to identify a person is to request a public document as a driver's license or ID card. Some services that won't be sure to identify ask a picture to prove the identity.

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  • 1
    Not all users have a drivers license or ID to share. Also from the perspective of privacy, some may not wish to share such information.
    – Tim Holt
    Commented Jan 28, 2021 at 23:47

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