Because of the high accuracy required in tidal analyses the best fitting tidal model regarding the information content of the record has to be found. InGeol. Fören. Stockh. Förh. 99 (1)A. J. Anderson describes methods for the analysis of tidal records and refers to his own reports. His paper and the reports referred to show that methods of analysis lack solidity and that the conclusions drawn from the result are not sufficiently proved. The present paper outlines advanced methods of tidal analysis which are needed in order to obtain significant data for geophysical interpretation. Fourier- and power-spectrum analyses are discussed with respect to signal-to-noise ratio before and after drift correction. Examples are given for the application of Fourier- and power-spectrum analyses as well as coherence to gravimeter records and tilt changes recorded by two Askania borehole tiltmeters. On the basis of this a more progressive method of analysis is described, and the results of different methods are compared. Finally some aspects of the interpretation of tidal parameters are discussed.