Complex response function obtained in reflection spectroscopy at the terahertz range is examined with algorithms based on dispersion relations for integer powers of complex reflection coefficient, which emerge as a powerful and yet uncommon tools in examining the consistency of the spectroscopic data. It is shown that these algorithms can be used in particular for checking the success of the correction of the spectra by the methods of Vartiainen et al. J. Appl. Phys. 96, 4171 2004 and Lucarini et al. Phys. Rev. B. 72, 125107 2005 to remove the negative misplacement error in the terahertz time-domain spectroscopy.