  Motivated by the recent numerical studies on the Chalker-Coddington network
model that found a larger-than-expected critical exponent of the localization
length characterizing the integer quantum Hall plateau transitions, we
revisited the exponent calculation in the continuum model and in the lattice
model, both projected to the lowest Landau level or subband. Combining scaling
results with or without the corrections of an irrelevant length scale, we
obtain $\nu = 2.48 \pm 0.02$, which is larger but still consistent with the
earlier results in the two models, unlike what was found recently in the
network model. The scaling of the total number of conducting states, as
determined by the Chern number calculation, is accompanied by an effective
irrelevant length scale exponent $y = 4.3$ in the lattice model, indicating
that the irrelevant perturbations are insignificant in the topology number
calculation.
