Preventing Duplicate Responses

The gf_unique merge field helps you prevent respondents from taking your survey more than once.

To add gf_unique to your survey and prevent duplicate responses:

  1. From your survey, select Distribute > Survey Link.
  2. Select Copy link.
  3. Add a question mark ? to the end of the link, then add the gf_unique merge field to your link using lowercase letters.
  4. Add an equals sign =, then enter a value for the merge field that will identify the respondent. This value could be a contactID, phone number, email or another unique identifier.

When you pass the gf_unique merge field value into your survey, the respondent with that identifier won’t be able to submit additional responses.

Test the merge field by adding ?gf_unique=yourname to the end of your survey URL. Your survey URL with gf_unique added for testing may look something like this:

GetFeedback's Salesforce Automation and Send to a List tools already includes gf_unique and gf_id email fields in the email template. If you use an external email provider to send your survey, you’ll need to add the gf_unique merge field to your link.

  • Add gf_unique to your Visualforce, HTML, or Pardot email templates by adding them as additional fields in your email template.
  • Match the syntax of the merge field value to your email provider.

Combine gf_unique with other merge fields to prevent duplicate responses, track each respondent, or personalize the survey experience.

You can use any parameter you'd like to identify respondents. If you use Email address to identify respondents your survey link might look like this:{!Contact.Email}

To prevent a contact from leaving a duplicate response and attach an email address, add the Email merge field. When you add two merge fields, your survey URL will have each merge field separated by an & symbol:{!Contact.Email}&Email={!Contact.Email}

Combine as many merge fields as you like. Pull in the respondent's name, email address, contactid, or their country code, in addition to using gf_unique.

The gf_unique merge field will only prevent responses after someone completes your survey gf_unique can't prevent duplicate incomplete responses. Once the respondent has completed the survey, opening the survey again after they’ve already completed will lead them to this page that reads "Your response for this survey has already been recorded."

If you have branding applied to your GetFeedback account or survey, the landing page will show the survey background image or color with the same message.