  The accuracy of absolute parameters' estimation in contact binary systems is
important for investigating their evolution and solving some challenges. The
Gaia DR3 parallax is one of the methods used for estimating the absolute
parameters, in cases where photometric data is the only one that is available.
The use of this method includes advantages and limitations that we have
described and examined in this study. We selected 48 contact binary systems
whose mass ratios were mostly obtained by spectroscopic data, in addition to a
number of photometric studies. The target systems were suitable for A_V and the
Re-normalised Unit Weight Error (RUWE), and their absolute parameters were
calculated based on Gaia DR3 parallax, observational information, orbital
period, and light cure solution from the literature and catalogs. The outcomes
of OO Aql differed significantly from those reported in the literature. Upon
analyzing the system's light curve with TESS data, we concluded that the stars'
temperatures were the reason for this difference, and utilizing Gaia DR3
parallax provided reasonable results. We displayed the target systems on the
Hertzsprung-Russell (HR), q-L_ratio, P-M_V, and logM_tot-logJ_0 diagrams, and
the systems are in good agreement with the theoretical fits. We showed that the
estimation of absolute parameters with this method might be acceptable if Delta
a(R_Sun) is less than about 0.1(R_Sun). There are open questions regarding the
existence of l_3 in the light curve analysis and its effect on the estimation
of absolute parameters with this method.
