  The accuracy of description of measured nuclear masses by presently used
nuclear-mass models is studied. Twelve models of various kinds are considered,
eleven of the global character and one local model specially adapted to
description of heavy nuclei. To decrease the number of nuclei over which the
accuracy is averaged, the global region (Z,N >= 8) is divided into four
subregions, in which the accuracy is studied separately. Still, to reach the
best precision, the accuracy is finally investigated without any averaging, for
each nucleus separately. The results are presented in a form of colored maps,
large enough to be easily and accurately read. Besides the accuracy of the
studied models, also their predictive power is considered. It is found that the
accuracy of description of mass strongly depends on a nuclear-mass model and on
the region of nuclei to which the model is applied. The best accuracy is
obtained by the recent two Chinese models WS3+ and WS4+. Generally, no clear,
strong correlation between the accuracy of description of already known masses
by a given model and its predictive power for new masses is observed. Still,
such correlation is found for separate models and in separate regions of
nuclei. More often for the macroscopic-microscopic models than for the other
approaches.
