SimMan -- A simulation model for workforce capacity planning Motivated by the difficulty in predicting the actual performance of workforce capacity planning solutions obtained from mathematical models, we develop a simulator, SimMan, to serve as a test bed for evaluating the effectiveness and robustness of different planning options and assignment rules. To facilitate the ease of use, the simulator is developed in C++ language with a modular structure so that different users or planners can customize the modules according to their specifications. We further develop a mathematical model for the workforce capacity planning problem, where the uncertainty of the demand is handled by the safety stock concepts. We also suggest a number of practical planning alternatives and assignment rules based on information from IBM. These rules are implemented as modules in SimMan and tested numerically to provide managerial insights