  Based on O II recombination lines we present a new calibration (called O
II[RL]) of Pagel's O23 indicator to determine the O/H abundance ratio in
extragalactic H II regions and emission line galaxies. The O II(RL) calibration
produces O/H abundances about a factor of two higher than those derived from
the T(4363) method with t2 = 0.00. The O II(RL) calibration has implications
for the study of different properties of emission line galaxies such as their
metallicity, star formation rate, and initial mass function. The O II(RL)
calibration also affects the abundance determinations based on other O/H
indicators, that include collisionally excited lines, like those known as O3N2,
N2, S23, Ar3O3, and S3O3. We argue that the controversy between the T(4363)
method and the photoionization models method to derive O/H values is mainly due
to temperature variations inside the observed H II regions.
