So, it's clear that Booleans can be "True" "False" and "undefined". Originally, I thought that all "undefined" also evaluated to "False" - but apparently that's not the case. Undefined != False. Therefore, I recommend having three buttons for checking booleans: [ CHECK-MARK ] [ X ] [ ? ] Where a user can check in the conditions for "undefined" booleans. FURTHER, I would recommend allowing for multiple buttons to be selected. In other words, you can select BOTH the [ X ] and the [ ? ] which would pass the condition if the boolean is EITHER [ X ] or [ ? ]. Thanks. Alternatively, the story could have a setting which says: "Treat all boolean unknowns as false"