  This talk summarizes results for all the scale independent renormalization
constants for bilinear currents ($Z_A$, $Z_V$, and $Z_S/Z_P$), the improvement
constants ($c_A$, $c_V$, and $c_T$), the quark mass dependence of $Z_O$, and
the coefficients of the equation of motion operators for $O(a)$ improved
lattice QCD. Using data at $\beta=6.0$, 6.2 and 6.4 we study the scaling
behavior of these quantities and quantify residual discretization errors.
