[en] A numerical framework is presented for the solution of the Landau - Lifshitz - Gilbert equation of magnetization motion using a semi-implicit Crank - Nicholson integration scheme. Along with the details of both space and time domain discretizations, we report on the development of a physically based self-consistency criterion that allows for a quantitative measurement of error in dynamic micromagnetic simulations. In essence, this criterion relies in recalculating from actual magnetization motion the imposed phenomenological damping constant. Test calculations were performed with special attention paid to the determination of suitable integration time steps. [copyright] 2001 American Institute of Physics