Working with Qualtrics

Qualtrics is a popular proprietary questionnaire and survey tool that is easy to pick up. Studies built with lab.js can be embedded in Qualtrics with a few simple steps; setting up the connection should take you about 10 minutes.

Before you go through the steps below, please make sure that you’ve prepared your study for use in third-party tools.


Qualtrics is prone to deleting data without warning. Specifically, as of March 2021, Qualtrics will truncate data saved from outside tools such as lab.js. This means that especially longer experiments run the risk of Qualtrics throwing away parts of the experimental data. They do not provide any indication that this is happening.

If you use Qualtrics, we implore you to make sure that your collected data is exported completely. Even if your study works perfectly in the lab.js builder, Qualtrics may still render the collected data unusable. We would very much like to spare you the pain of losing data.

Especially if you are new to online data collection, please consider using a service such as Open Lab instead; the experience is much smoother and the caveats fewer.

Set up data storage

As a first step, you’ll need to create a place to store the data. In Qualtrics, most data will come from survey questions; our external study will need an embedded data field where it can place the collected data.

You’ll can add an embedded data field in the survey flow dialogue, like this:


The following steps assume that you’ve called the field labjs-data. If you’d prefer a different name, or if you’re combining several experiments in a single survey, please adjust the JavaScript snippet below.

Embed the study

Next, you’ll need to pull in the study you’ve built. As described in the introduction, you’ll need to host your study externally and embed it in the survey through an <iframe> tag.

Because the data is saved in the embedded field you set up above, the study is best inserted in a Descriptive Text component in Qualtrics, rather than a question of its own. After you’ve inserted the new component, please click on its contents and change to the HTML View to insert the snippet below. You’ll need to change the URL at the top to point to the study you’d like to embed.

<!-- Embed the study -->
  style="width: 100%; min-height: 600px; border: none;"

<!-- Adjust the page style slightly -->
  /* Remove border from last question */
  .QuestionOuter:last-of-type .QuestionText {
    border: none;


Qualtrics requires that the study be accessed via an encrypted connection, so please make sure that the link you insert starts with https.

Connect the study and the questionnaire

The next step is to link the behavior of the questionnaire and that of the study. The questionnaire should collect and store the generated data, and move to the next page after participants have completed the experiment. This requires a bit of logic, which is added to the question you created in the last step.

To achieve the connection, you’ll need to add JavaScript logic to the Descriptive Text question, inserting the following code inside the curly braces of the addOnReady block. This snippet can stay as-is, unless you’d like to store the study data in a different embedded data field.

const page = this

// Listen for the study sending data
window.addEventListener('message', function _labjs_data_handler(event) {
  // Make sure that the event is from lab.js, then ...
  if ( === '') {
    // ... extract the JSON data lab.js is sending.
    const data =

    // ... save data and submit page
    Qualtrics.SurveyEngine.setEmbeddedData('labjs-data', data)
    window.removeEventListener('message', _labjs_data_handler)


If you deploy a study to Qualtrics, please make absolutely sure that you’ve thoroughly checked the collected data, especially if you’ve made changes to the data storage code.

Working with the collected data

After setting up the survey and study as described, and going through the survey, you should see the collected data in the ‘Data & Analysis’ tab. It should appear as a single column of somewhat unwieldy data, named labjs-data (unless, that is, you’ve changed this name).

The somewhat garbled appearance is because, like other questionnaire-focussed tools, Qualtrics enforces a wide data format, requiring a conversion step to decompress the data from lab.js before further analyses can be done. This step is also required with other, similar tools, and therefore described in the general documentation.


If you can see the experiment embedded in the survey, but aren’t redirected to the next survey page after completing the experiment, or if you don’t see the collected data, please make sure that your experiment doesn’t get stuck on the last screen. For example, you might set a timeout on the last screen, or allow participants to respond to your goodbye message.

Without this, Qualtrics will not count the dataset as a complete response, and will exclude it from the data export.