[en] The main task of an NDT engineer is to select the best method, considering the cost-benefit value of different available systems and taking into account the special existing constraints. The aim of the paper is to suggest a tool that will enable characterization of measuring systems. The derivation of the characterization parameters and functions has to be general, i.e., suitable for all possible measuring methods, independent of their principle of operation. Quite often the properties measured during the NDT procedure are not the wanted ones, but there must be a correlation between the measured property and the performance of the product. One has to bear in mind that the ultimate choice between systems is not, in practice, just based on the mathematical optimization approach that is presented. Factors like cost-benefit, availability of trained manpower, service, real-time information, weight, volume, etc., may be crucial problems, and they may well dictate the final selection