Correlation between effective yield y_eff(O) and rotation speed V_rot for spiral and irregular galaxies. (a) Average O/H is assumed to be the value at one disk scale length. Stellar masses are derived using color‐dependent M/L ratios based on synthesis models of Bell & de Jong (2001). (b) Same average O/H as in (a), but using constant ﹩M/ L=2﹩ for spiral disks. (c) Average ﹩\mathrm{O}\,/ \mathrm{H}\,=\mathrm{O}\,/ \mathrm{H}\,﹩ at one disk half‐light radius; constant M/L as in (b). The horizontal dashed line shows the value of the solar oxygen mass fraction; this is for illustration purposes only.