Theoretical models for the chemical oxygen-iodine laser (COIL) depend on a variety of assumptions and empirical data to provide closure and simplify solution of the governing equations. Among the various assumptions and empirical data built into models for COIL are assumptions regarding steadiness in the time domain and which kinetic processes are significant in addition to the measured values for the rates at which the kinetic processes occur. The work discussed here is directed toward elucidating and increasing the understanding of the assumptions underlying COIL models and the implications for the modeled physical processes underlying the COIL, driven by current directions in the development of this technology. This is directly linked to efforts to achieve improved COIL efficiencies and performance, since excursions well outside traditional operational parameter space are necessary. As such excursions are made, the distance from the traditional parameter space where COIL models have been baselined and validated becomes much greater, increasing the importance for understanding the factors that influence the accuracy of the simulations. In this role of increasing the level of understanding regarding the limits to the accuracy of COIL models, these simulations provide information important to current work investigating configurations and operating conditions well outside of the traditional parameter space.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.