Sometimes, people want that only people who have been invited can participate in a survey. This can be done. The steps are as follows:
Create a list of random codes that people cannot just guess. The random code can consist of letters or numbers (or both), including non-latin characters (e.g., Asian characters)
Give each participant you want to invite one of these codes
In your survey, have the a check if one of these numbers are entered in a text line
Run the demo
Have a look at what you will get first. You can only go to the question about potatoes if you enter one of the four following codes (you can include UTF-8 non-Latin characters, such as Chinese characters).
Use one of these (copy one to try out the survey and see if it works). Also check what happens if you enter a non ID, that will lead you to the end of the survey straigtaway.
Complete survey code
l: enter_id t: textline q: You can only do this survey with the special invitation code. - Enter the code you have been given: l: check_id t: jump - if $enter_id = 234243343421 then goto question1 - if $enter_id = A234316-X-32 then goto question1 - if $enter_id = SomeRandomWord then goto question1 l: not_welcome t: info o: end q: Sorry, you do not seem to have an invitation. You can now close the browser window or tab. Goodbye! l: question1 t: radio q: This is part of the invited survey. Do you like potatoes? - Yes, I like potatoes a lot - No, not at all