Custom variables are special variables that can be used on a survey for displaying dynamic text or for logic or for storing metadata along with the respondents response.
You can dynamically update custom variables to store additional data along with the respondents response using the update variable logic.You can update custom variables anywhere on the survey. To update variables, go to:
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Under the workspace, click on the logic option for the question where you would like to update the variables.Following options are available: