You have created a survey choosing Google Forms but people have quickly figured out an effective way to game your poll and tilt the answers in their favor. They are sending multiple entries, and because Google Forms isn't going to record the I. P. address or the e-mail of the form submitter, it is nearly impossible for one to separate the duplicate submissions from the actual entries.
How do you restrict Google Forms to only allow one single entry from a user?

If you can be a Google Apps user, you can always restrict the Google Form to accept entries only from users who are area of your domain and the response spreadsheet will then record the username of the create submitter. However if you have the usual Gmail / Google Account, you have another option now and hence avoiding multiple form submissions from the equal user.

While creating the Google Create, click the Settings bar and switch it on the option that says “Allow singular response per user. ” When the initial option is enabled for a Google and bing Form, respondents will have to sign-in by their Google account to access the create. Their email address won’t be recorded on the response sheet but Google Form isn't going to allow another entry from the equal Google Account.

If someone tries to make sure you fill the Google Form again, a warning message would be displayed saying “You’ve already responded. You’re able to only fill out this form at the time. Try contacting the owner of the form signs this is a mistake. ”

This is by far the easiest approach though as well as put your Google Form out of reach of people who don't need Google Account or those who are skeptical of associating the e-mail address with their form entry (though this association seemingly hidden from the form owner).