The psychological factors influencing the common test-situation of the ABLB are still unknown. The fact that always on the same ear the intensity is remaining constant and that this intensity is increased in equal steps is no longer due to modern psychological principles of testing. Both--the side and the intensity--should be randomized within the given range (both sides and all possible intensities). Therefore the test-procedure is controlled by a computer, which also calculates the significance of the relative recruitment. When the test is finished a diagram is plotted containing the values and the regressionline. Also the monaural test (comparison of two frequencies) is well practicable using the same program, because the incertainty (being greater if the test is more difficult) is included in the statistic calculation.