Comparison of a variable on a list

Hello everybody
I would like you to have a help concerning a validation of a question

let me explain:
-I have a text type question whose variable is A1.

  • Another list type question whose variable name is B1.
    I want to check if the content of the variable A1 is on the list B1 if it is the case it is okay on the contrary send an error

Try validating as follows:

B1.Any(x => x.Item2 == A1)

See Syntax Guide: List questions

You probably want to check that the household head or a respondent is mentioned in the list of the members. Don’t do what you’ve described. Instead use a linked single select question.