The Fallback VEE Group is a configuration option that allows you to specify a VEE Group to be used when no other VEE Group is found for a measurement. This ensures that the measurement is processed by the VEE rules defined in the Fallback VEE Group, which can include estimation rules. The Fallback VEE Group is assigned to a VEE role, which is a logical grouping of VEE Groups based on the source and type of measurement data. For example, you can create a VEE role for estimated measurements and assign a Fallback VEE Group that contains the estimation rules you want to apply to them. This way, you can ensure that the estimated measurements are validated and edited according to your business requirements. References: Configuring VEE Roles, Understanding VEE Rules