The ability to calculate composition in composition spread thin films is a powerful tool in combinatorial research. This ability is pivotal in high-throughput studies, where the time and effort required to determine elemental compositions using standard techniques can be prohibitive. Calculating codeposited film composition from single-source deposition profiles requires a model for film growth in codeposition. In dc magnetron sputtering, modeling film growth as the simple addition of individual rates can lead to significant errors, primarily due to resputtering of film atoms by energetically reflected gas atoms. We develop a model which includes the definition of a resputter coefficient that is used to calculate resputtering rates in the codeposition of an arbitrary number of sources. The accuracy of the model is demonstrated for the codeposition of Pt and Pb. In the development of the model, useful parametrizations of fundamental quantities of sputter dynamics are presented, and the authors also present tabulated values of the resputter coefficient for 27 commonly sputtered elements at select sputter voltages. (C) 2008 American Vacuum Society.