Sign up, it's free!

Tracking & Identifying Respondents Using External IDs & Custom Survey Links

Add an external ID to your share link, to get an additional level of identification of respondents. In many cases you need to be able to identify:

  • exactly which one of your respondents have responded to your survey,
  • or how many times each respondent have responded to the same survey.

To address this need, we have implemented a feature called “External ID“. This feature allows you to pass along a custom ID when loading the survey. The ID can be anything you want. For instance you can unique links for each one of your respondents using their email addresses. The ID is actually included in the URL that your participants receive from you. You can make unique survey links for each respondent (e.g. when sending out emails to an audience group using companies that offer panelists like Cint), or make unique links of the same survey for different occasions, periods, or locations.

This way, the ID will be included in the link that your participants receive from you. When they take the survey, this ID is automatically stored together with their response, and when exporting collected survey data to Excel or CSV files, you can easily find it in the last column under the title of “External id”. You can also see the External IDs in the Individual Responses view.

External IDs could of course be used for many reasons. For example, let’s imagine I have a brand and two shops located in two different Swedish cities of Stockholm and Malmö, and I want to do a research about customer satisfaction of each individual shop. So I would send them a customer satisfaction survey, but to make it shorter and faster for respondents, instead of directly asking them which shop they visited to buy my products, I would add the location inside the survey link itself, like this:


and send one of the links to the email list of my Stockholm customers; and the other one to my Malmö based customers. This way, by looking at the data, we’d know which group each respondent belongs to, without even having asked them directly.

How to use External ID to identify individual respondents.

In short, you have to create a custom survey link for each one of your respondents, and send them their respective custom link. For example, you can append the participant’s email or their name, or anything that you can associate them with, at the end of the URL of the survey.

Generating links with external IDs

To add External IDs, you must use the long link. To do so, you can use the link generator function in the SHARE step, which is located right under the short link. Just write what external ID you want to use, and the system automatically generates the link for you.

In our system, short-links are provided only for an easier sharing. However, you can not use the short-link that you get in the SHARE step.

For instance, if your respondent’s email is, you maybe decide to include the email in the survey URL and create a unique survey link for him, using the link generator in the SHARE step, which will generate something like this:

Generate a link with an External ID

Note that the external_id is added after the ~ sign, at the end of the survey link.
To get the long link of your survey, you can also open the short link first in a browser tab, which will automatically convert it to the long-version. Then copy that from your browser’s address bar and add the external id to that.
Don’t use space characters in your custom links. It’s better to separate the words with dashes “-” or underlines “_”.

How External IDs are shown to you

There are two ways you can see the External IDs.

In exported data

One of them is when you export your collected data, like the example below.

Each row in the Excel file represents one participant or participation.
Did you come to our seminar last week? How satisfied are you with the following aspects of the seminar? What is your current position? External id
Yes Satisfied Supervisor
Yes Satisfied Marketing
No N/A Accounting
Yes Very satisfied IT

* The above data are fake.
The above table shows an example of a downloaded spreadsheet file. First row shows survey questions, and each of the next rows represent one respondent. In this example,


In “Individual Responses” view

The other way is by going to the individual responses view. The IP-addresses are stated for each respondent, under the Metrics tab.

An illustration of individual responses, showing how IPs and External IDs are shown to survey creators.

The illustration above shows an example of what is shown under the Metrics tab in the Individual Responses view. Note how IPs and External IDs are shown to survey creators.

Limiting number of participations

SurveyLegend allows you to limit the number of participations. If this feature is enabled, a respondent can participate in a survey only one time, from the same browser. Read more about limiting number of participation in a survey here.

This feature uses cookies to work. Therefore, if a respondent opens your survey link in another web-browser, or cleans the browser’s cache, they can participate in the survey again.

But if you want to make sure that a respondent does not “cheat”, it’s a great idea to add an external ID to the link that you send them. This will empower you to track how many times respondents have actually provided their feedback.

Making it harder to “cheat”

If you use the participant’s name, email address, or something that is meaningful and recognizable for them in the link, they might notice it in the survey link. In some cases you might prefer to keep it as a secret, to be able to verify the quality of the collected responses.

So to make it harder for recipients to recognize their custom made external ID, you can add a randomly generated ID, which only you know to whom it belongs.

Using different IDs for different sources of feedback

Usually you want to share the same survey on different platforms. For example a survey can be shared on Facebook or Twitter, or be sent via email, or even embedded into a web page.

Some researchers might not be interested in tracking each individual respondent, but might prefer to instead analyze the traffic and see from which sources are the responses coming from.

In this case, you can simply make different URLs, and use the source as an ID.
For instance:

User guide

Become a Legend Now ;)

Make your 1st free online survey today!

starMobile-ready surveys
starUnlimited responses
starLots of amazing features!