Recipe: consent and screening from a single link

What you get: one link you can put on a poster, an advert or a study web page. Someone opens it, reads your information sheet and consents. The moment they do, they are shown — and sent — a link to your screening questionnaire. Their answers are scored automatically, and eligible people are turned into participants and messaged, without anyone on your team touching a keyboard.

What you need: eConsent enabled, one stage in questionnaire mode, and a pool of unallocated participants.

This recipe assumes you have read the two articles it builds on. Set each piece up there first, then come back here for the joins:

This recipe puts consent before screening, which means you will hold signed consent forms from people who then turn out to be ineligible.

That is a legitimate design, and often the right one: your screening questions may themselves be sensitive enough to need consent before you ask them. It is also not the only option — screening first and consenting only those who pass keeps your consent records tidier, and is the better fit when screening is a couple of harmless demographic questions.

Which way round you go is a question for your protocol and your ethics committee, not a technical one. If you screen first, the same building blocks apply in the opposite order: the screening questionnaire's on-screen message carries the consent link instead.

Step 1 — Build the screening questionnaire first

Build the screening stage before the consent form, because you need its public link to finish the consent side.

Follow Screening questionnaires to:

  • create the stage and enable questionnaire mode;
  • require an email address under Contact details — this recipe depends on it;
  • tick It must already have consented to this trial beneath it, so the questionnaire only accepts the address someone consented with;
  • add scoring rules to your eligibility questions;
  • add the rules that act on the score.

Then copy the general link from the Questionnaire tab. It looks like https://app.trialflare.com/q/<stage id>.

Use a custom link instead. Rather than the general link, create a custom link named something like "Post-consent" with an attribute source = econsent. Every submission that arrives through it is tagged, so you can tell the people who came through your consent flow apart from anyone who was sent the screening link directly.

Now open Consent > Informed consent forms and go to the Settings tab. Three fields do the handover, and you want all of them.

Continue to a questionnaire puts a button at the end of consent that takes the person straight to the questionnaire you pick — only stages with questionnaire mode enabled are offered, since they are the ones with a public link. Give the button whatever wording suits your study, or leave it to say Continue to the next step.

That button does two things a pasted link cannot. The contact details they gave on the consent form are carried over, so they do not type their email address twice. And the response they submit is linked to the consent they just gave — it appears in the Consent column on the questionnaire's responses, alongside a link to the signed form, and the signed consents list gains a Screening column so you can see at a glance who has consented but not yet been screened, and open anyone's answers straight from there.

The questionnaire you continue to must verify an email address or phone number — that verification is what ties the response back to the consent, so a questionnaire that verifies nothing cannot be chosen.

The button carries a link that identifies their consent, so it is personal to them and lasts seven days. Tell people not to forward it. If they do, it is not a way in: whoever opens it must still verify the details they enter, and the response is only filed against the consent when what they verified is a detail that consent holds. Someone else filling the form in simply produces an ordinary unlinked response. The contact details are filled in only for someone arriving straight from consent — within half an hour — so a link that is forwarded or found in a shared browser later does not show them. Someone coming back after seven days gets the ordinary questionnaire.

Add the link to the two message fields as well, so closing the tab is not fatal.

Post-consent on-screen text is displayed the instant consent is submitted. It is rich text, so add a proper link:

Thank you for consenting to take part.

The next step is a short eligibility questionnaire, which takes about five minutes. Start the questionnaire

We have also emailed you this link, so you can come back to it later.

Post-consent notification is the copy they keep. It is capped at 400 characters, so keep it tight and paste the URL in full:

Thanks for consenting to join . Please complete our short eligibility questionnaire to finish signing up: https://app.trialflare.com/q/...

Save the consent form.

Mind the WhatsApp gap. The post-consent notification reaches participants by email, and by SMS where they gave a phone number and are not using WhatsApp. It is not included in the WhatsApp confirmation message. Anyone who consents via WhatsApp alone will only ever see the on-screen text and the Continue button — which is exactly why this recipe puts the link in both places.

Step 3 — Decide what happens after screening

Your screening rules now carry the flow forward. A typical set:

Rule 1 — eligible. Condition: score greater than your threshold. Actions:

  • Mark as successful.
  • Allocate to next unallocated participant.
  • Email participant: what happens next, and how to download the app.

Rule 2 — not eligible. Condition: score less than your threshold. Actions:

  • Mark as unsuccessful.
  • Show on-screen message: a short, kind explanation, and who to contact with questions.

Rule 3 — everyone. No conditions. Action:

  • Show on-screen message confirming their answers were received.

Because the eligible rule allocates a participant record, you can go further under Messages > Automatic and add a message triggered by completing the screening stage. That message goes through the study's own messaging thread, can carry attachments, and can be sent by email, SMS or WhatsApp — a better fit for onboarding instructions than the plain-text rule action.

Step 4 — Keep the participant pool stocked

Allocation draws from the oldest unallocated participant record in the study. If the pool is empty when someone passes screening, they are not allocated — the response is simply left unallocated for you to deal with by hand.

During active recruitment, check the pool regularly and top it up. It is the one part of this flow that runs out quietly.

Step 5 — Test the whole chain before you publish

Walk the flow yourself, end to end, on a phone:

  1. Open the consent link and consent with your own email address.
  2. Check the on-screen text appears and its link works.
  3. Check the confirmation email arrives, with the PDF attached and your notification text at the bottom.
  4. Follow the link and submit the questionnaire with answers you expect to pass.
  5. Confirm in Questionnaires that the score is what you expected, the status went green, and a participant was allocated.
  6. Repeat with answers you expect to fail.
  7. Delete your test response and reset the participant record before you go live.

The most common thing to get wrong is a scoring threshold that does not mean what you thought it did, and that only shows up when you submit a real answer.

What this flow will not do for you

Only submissions that came through the button are linked to a consent. Someone who reaches the questionnaire by its own link still submits an unlinked response, even if they consented an hour earlier. The Screening column on the signed consents list tells you which is which; match the rest on the email address when you come to allocate people.

Nothing stops someone screening without consenting, unless you say so. If the screening link is shared onwards, submissions can arrive from people with no consent on file. It must already have consented to this trial closes that off: the form then only accepts a contact detail that appears on a completed consent, and makes the person verify it, so a shared link is no use to anyone who has not consented. Without it, your custom link attribute is what tells them apart — submissions tagged source = econsent came through your consent flow, and you should check before allocating anyone who is not.

Consent is still a gate on the study itself. Even if a screening submission is allocated to a participant record, that person cannot take part until they verify the contact details they consented with when they first open the app. That check is doing real work — leave it in place.