External Recruitment: How to buy participants for your OpinionX surveys

Need to buy participants to complete your OpinionX survey? You're in the right place! This guide contains everything you need to know about using external recruitment platforms to source participants for your OpinionX surveys.

The most commonly used platforms for recruiting OpinionX survey participants are listed below. Click any platform's name to read its setup guide.

Prolific is our top recommendation. If you use a provider not featured here, let us know ([email protected]) so we can add it to our list.

All of these features are available to all users on OpinionX's free tier:

Here are the steps required by most third-party platforms for recruiting survey participants, assuming you've already created your survey:

Most recruitment platforms require survey tools to collect data like a participant ID and project ID. Typically, this is done inside the survey URL rather than asking the participant to type it into the survey themselves, as this can lead to mistakes that cause problems for you later on.

Go to the Enrichment Tab and click 'Manual Setup' to create enrichment fields for each required data field. For this example, I've added three data fields — PROLIFIC_PID, STUDY_ID, and SESSION_ID (these are the three data types that Prolific requires). For IDs, you should use the 'Unique' data type, as shown below.

To pull these three data points from the recruitment platform, we need to create Hidden Fields inside the survey URL. All you have to do here is click the "Hidden Fields" button on the Enrichment Tab:

As you can see above, this creates a link with sections for each of these data fields (the PROLIFIC_PID field is highlighted in the link). The link includes the survey access code at the start and then the hidden fields at the end, with a specific character in the middle to indicate that the Hidden Fields section has started. On some survey tools, this character is required to be a ? while on others it must be a #. On the Hidden Fields popup menu, you'll see a dropdown option called "Query Type" where you can decide which character is used.

Hit "Copy Link" on this menu to grab this full link. This is the link you'll put into the recruitment platform that participants will use to access your survey. When each participant opens this link, the recruitment platform will fill in the {{value}} sections with the relevant data:

Generic link with Hidden Fields structure:

Personalized link that is dynamically created by the recruitment platform:

Some survey tools require the {{value}} section to have a specific format. For example, Prolific uses the structure:

This really makes no difference! As long as the field name (eg. ?PROLIFIC_PID=) is identical on the recruitment platform and OpinionX, then it will work!

Some recruitment platforms require separate finish pages for different types of participants, such as those who successfully complete the survey (Completes) or people who didn't meet your screening criteria and were removed from the survey early so they shouldn't be paid the full incentive (Screen Outs).

To do this, you'll need to create many finish pages. Go to the bottom of your Survey Setup tab and click the "Edit Finish Page" button. There you'll see an option called "Add Another Finish Page." Use this to create separate end points for each type of survey, including a different redirect link for each.

Once you've created your Multiple Finish Pages, go to any question in your survey and you'll see all of your Finish Pages listed as potential destinations to send participants. You can then use branching logic to send incompatible participants directly to a "Screen Out" Finish Page.

It's common to send participants back to the recruitment platform at the end of the survey to confirm they finished it. Most platforms have an automated process for this, where the participant's ID is included in the URL when they finish the survey, which is captured by the recruitment platform and logged as a "complete".

On the Setup Tab for your OpinionX survey, go to the Finish Page, click the customization icon (⚙️) and enable "URL Parameters". If you have already set up hidden fields at the start of this process, those fields will appear as URL Parameters automatically without you needing to do any other configuration:

You can find a full library of guides for common recruitment platforms here.