A method determines at least one parameter for a process quality during a processing process. The method includes: processing a workpiece while moving a processing tool and the workpiece relative to one another; monitoring a region on the workpiece; determining the at least one parameter for the process quality based on the monitored region; and determining at least one position-dependent parameter for the process quality based on a plurality of measured values of the at least one parameter at a same processing position, or determining at least one direction-dependent parameter for the process quality based on the plurality of measured values of the at least one parameter in a same processing direction.