People trust their lives with human-machine systems such as airplanes every day, making it critical for system designers to prevent human errors and accidents. Cognitive work analysis (CWA) is a method developed to analyze the cognitive requirements of such system to inform the design process. Nonetheless, because CWA was developed to deeply analyze the system, as it was originally introduced, it was not readily applicable to system design and design decision making. On the other hand, simulation modelling has been used to provide quantitative metrics for decision making. However, it lacks a comprehensive framework for modelling based on model analysis. In this research we propose the Cognitive Work Analysis and Simulation (CWAS) method to bridge the gap between analysis and simulation by using the CWA results to build a dynamic representation of the system. The simulation model provides quantifiable measures of performance, such as mental workload of system agents, which facilitates design decision making. In addition, CWAS provides a profound framework for simulation modelers in modelling. The CWAS method is demonstrated in a case study on the work process of Advanced Cardiac Life Support. CWAS adds value to the CWA research methodology by providing a structured process for using system analysis as a modeling basis for cognitive behavior simulation modelers. CWAS is meant to add value a step before actual prototyping in the product and system life cycle, making it possible to examine a larger variation of design scenarios before deciding on prototyping options.