I have a list type question (radio), where the values are populated from five custom attributes in the participant table.

The values are phone numbers.

Not all participants have five phone numbers, so in some cases the list would have sub-questions with the value "None".

I want to prevent the question from submitting if the respondent chooses one of the radio options with the value "None".

How can I do this?

Since LS is still lacking a answer relevance, you would need to create a Question validation equation.

Other workarounds (which might work):
1. Create a multiple short text question with default answers filled with an equation that fills only when NOT NONE. Hide this question via CSS and use that question as array filter on your radio list question. That should filter all NONE entries.

2. Use a Multiplechoice question with subquestion relevance. Limit answer to max. 1

I would do it via question theme to use conditions via Twig.

Maybe use JavaScript to remove all "None" options.

Array filter with multiple short question text was the "simplest" approach! Thanks

LouisGac wrote: I would do it via question theme to use conditions via Twig.

Well
www.limesurvey.org/forum/future-features...ubquestion-relevance