Capture External Data

What is the External Reference Variable?

External Reference Variable is an another variable which can be used to pass in data to the Survey. The External Reference variable (ext_ref) is used to associate responses to their respondents. You can assign an ID number or anything else that will uniquely identify a respondent to the ext_ref variable. When the results are collected, the ext_ref variable is captured and stored with the other data.

How can I use the ext_ref variable with my own email program?

Every survey that you create will have a unique URL. To include other data to be captured along with the survey data you just need to add the ext_ref parameter to the URL. For example:

Replace xxxx with your unique id for the respondent.

I am using a customized URL. How can I pass the ext_ref variable in the customized URL?

The ext_ref parameter can be passed along with the URL by appending the suffix “?ext_ref=xxxx” to the URL as shown in the following example.

The ext_ref tag is appended as follows:

Are there any limitations to the ext_ref variable?

  • The External Reference Variable can store up to 64 characters.
  • You can use alphanumeric characters (A to Z, a to z, 0 to 9).
  • Accented characters or characters from languages other than English may not get saved. Please limit the character use to English.
  • You cannot use the pound/hash [#] in the External Reference Variable.
  • We recommend you not use commas and quotation marks (single or double) in the ext_ref variable.

How can I use the ext_ref with the QuestionPro Email List Manager?

If you are using the email list management interface to send out email, add the following tags to your survey invitation:


The &ext_ref variable is automatically captured in the raw response data.

Note: The mail merge tags are special variables that are used in Email List Management in tracking the email addresses of respondents. Simply append the &ext_ref=xxxx to the end of the mail merge tags.

License & Access Options
This feature/tools described here are available with the following license(s) :

  • Unlimited Surveys, Questions, Responses
  • Advanced Toolset and Features
  • No Long Term Commitment