Validation criteria - two mutually exclusive answers

[Kal_Lam]

@ChannavanLeijsen, maybe this post discussed previously should help you solve your issue:

How to set a constraint (validation) while selecting a response from a Multiple Choice Question

In this case, maybe you could do it as shown in the image shared below using this expressions in the constraint: not(selected(., ‘c’) and (selected(.,’a’) or selected(.,’b’))) and not(selected(., ‘d’) and (selected(.,’a’) or selected(.,’b’))) In the survey tab of your xlsform: [Image 1] In the choices tab of your xlsform: [Image 2] Data entry screen as seen in Enekto: when data is entered as expected [Image 3] Data entry screen as seen in Enekto: when data is not entered as expected …