A method and an apparatus for determining the quality of a gearing system is described. The method includes the steps of setting a sequence of target angles of rotation of a first gear wheel, measuring for each of the target angles of rotation an output angle of rotation of a second gear wheel, and calculating a plurality of theoretical output angles of rotation. The method also includes obtaining angle of rotation differences between the plurality of output angles of rotation and the plurality of theoretical output angles of rotation, forming a sequence of cumulative values, and determining, based on the sequence, a first amplitude value, a second amplitude value or a third amplitude value.