The effect of Nb on the hysteresis parameters of sol-gel Pb-1.1-x/2(Zr0.53Ti0.47)(1-x)NbxO3 (x = 0.0 - 0.05, increments of 0.01) thin films is reported. Two sets of (111) textured films, rapid annealed at 600 and 650 degrees C, were studied. The degree of texture and grain size as a function of Nb was analogous for the two sets. Surface coverage by a pyrochlore phase increased with Nb addition, however its quantity and distribution was determined by the annealing temperature, being less for the 650 degrees C set of films. For the two sets a strong continuous decay of the remanent and maximum polarizations, and the slope at the coercive field, (dP/dE)(Ec), was observed with increasing Nb. The remanent polarization was reduced by a scaling factor at any given field, yielding no changes in the saturation profiles as a function of doping. The difference of the maximum minus remanent polarization and the width of the loop were not influenced by Nb at any given field. A linear increase in coercive field asymmetry (up to 40kV/cm) was observed with Nb addition, yet was field independent and thus electrostatic in origin. A methodology for isolation of Nb induced microstructural effects from bulk or defect modifications was developed. The comprehensive set of hysteresis parameters required for such an analysis is presented here.