We examine the variability of the high-ionizaton C iv \lambda { 1549 } line in a sample of 105 quasars observed at multiple epochs by the Sloan Digital Sky Survey .
We find a strong correlation between the change in the C iv line flux and the change in the line width , but no correlations between the change in flux and changes in line center and skewness .
The relation between line flux change and line width change is consistent with a model in which a broad line base varies with greater amplitude than the line core .
The objects studied here are more luminous and at higher redshift than those normally studied for variability , ranging in redshift from 1.65 to 4.00 and in absolute r -band magnitude from roughly - 24 to - 28 .
Using moment analysis line-fitting techniques , we measure line fluxes , centers , widths and skewnesses for the C iv line at two epochs for each object .
The well-known Baldwin Effect is seen for these objects , with a slope \beta = -0.22 .
The sample has a median intrinsic Baldwin Effect slope of \beta _ { int } = -0.85 ; the C iv lines in these high-luminosity quasars appear to be less responsive to continuum variations than those in lower luminosity AGN .
Additionally , we find no evidence for variability of the well known blueshift of the C iv line with respect to the low-ionization Mg ii \lambda 2798 line in the highest flux objects , indicating that this blueshift might be useful as a measure of orientation .