Resistivity of two-dimensional systems in a magnetic field at the filling factor 1/2

Experimental data available in the literature on the diagonal resistivity of GaAs/AlGaAs heterostructures in a magnetic field at the filling factor 1/2 have been compared with the existing theoretical prediction [B. I. Halperin et al., Phys. Rev. B 47, 7312 (1993) and F. Evers et al., Phys. Rev. B 60, 8951 (1999)]. It has been found that the experimental results disagree with the prediction.