#1 by Sarah

Hello, 

I am trying to make one comprehension question such that participants can choose several choices instead of one choice. The correct choices are among all the options. If they give correct answers they continue with the experiment. If not, there is an error that says please try again. They cannot proceed with the experiment unless they give the correct answers (choices). Does anyone know how can I do that with multiple options and the error?

#2 by Chris_oTree

See multi_select and multi_select_complex in otree-snippets.

#3 by Sarah

Yes, I tried that. But I do not know how to arrange the error. I want them to answer the correct choices, not anything they want. 

Can you help me with the error?

#4 by Chris_oTree

Use error_message.