  We have applied the Baade-Wesselink method to two field RR Lyrae stars, i.e.
SW And and RR Cet, and derived their distances and physical parameters. With
respect to previous B-W analyses we have applied the following improvements: a)
use of all sets of available data, after proper comparison for homogeneity and
compatibility; b) use of the most recent and accurate model atmospheres, with
turbulent velocity V(turb) = 4 km/s and the no-overshooting approximation, and
comparison with other treatments of convection; c) use of the instantaneous
gravity along the pulsation cycle rather than the mean value; d) comparison
with modified radial velocity curves according to various assumptions on radial
velocity gradients in the atmosphere; and e) careful reanalysis of the
temperature scale. The main aim of this study is to evaluate the effect of the
above items on the B-W results and verify whether any (or a combination) of
them can possibly account for the discrepancy of the absolute magnitude
zero-point with respect to other independent determinations.
