How to collect an ID (Mturk Prolific etc.) from the URL
Often, you'll want to connect a formr survey to a participant pool such as Prolific Academic or Amazon MTurk. For many of these platforms, users have worker ids. They can enter these by hand, but it is an error-prone process. Preferably, they get a customised link that will include their worker id, so that formr stores it automatically.
Here is an example spreadsheet. It expects people to show up to your study with a link ending in ?code=MYWORKERID.
If they enter without it, they will be blocked from participating. Try it out: https://get-id-from-link.formr.org/
https://get-id-from-link.formr.org/?code=MYWORKERID1020 on the other hand should work (you might have to open it in an incognito window to reset cookies).
If you name your survey get_id_from_link and the item code as in the example, you can access this code through R in the study. You might want that for the next step.
For Prolific, you need to specify sending the Prolific ID with the link when setting up your survey there. The option is hidden in the advanced settings of the "study link" block (see screenshot):
Some survey providers want users to come back to "complete" the study.
You can do this by adding an external unit with the completion link, like so
https://app.prolific.ac/submissions/complete?cc=I2PWSFRG
(Substituting whatever link they want to use).
Other providers may need you to additionally add the participant ID to the URL. To attach it to the email, you can add an External unit at the end of the run with the following syntax:
paste0("https://surveyprovider.com?code=", get_id_as_url$code)