The influence of experimental variables on the accuracy of multicomponent kinetic-spectrophotometric determinations using multivariate calibration techniques is reported. Kinetic and spectral angles are introduced and shown to be good descriptors of the quantity of analytical information present in kinetic-spectrophotometric data. The components of these descriptor angles are described. The effects of instrumental noise and rate constant fluctuation are contrasted. An equilibrium spectrophotometric determination of gallium(III) and nickel(II) is compared to a kinetic determination and a kinetic-spectrophotometric determination. The effect of changing experimental variables (e.g., pH and wavelength range) is discussed, and conclusions are drawn. (C)2000 Elsevier Science B.V. All rights reserved.