  It is shown that the statements about the observation of the transitions
between the insulating phase and the integer quantum Hall effect phases with
the quantized Hall conductivity $\sigma_{xy}^{q}$ $\geq 3e^{2}/h$ made in a
number of works are unjustified. In these works, the crossing points of the
magnetic field dependences of the diagonal resistivity at different
temperatures at $\omega_{c}\tau \approx 1$ have been misidentified as the
critical points of the phase transitions. In fact, these crossing points are
due to the sign change of the derivative $d\rho_{xx}/dT$ owing to the quantum
corrections to the conductivity.
